Thursday, July 24, 2014

Starlight Xpress Slimline OAG

SBIG STF-8300M, Starlight Xpress 7 position 36mm USB filter wheel, Starlight Xpress OAG w/QYH5L-II camera, M48 adapter, 6.4mm M48 spacer, Astro Physics CCDT67 Telecompressor.

The off-axis guider (OAG) is another item I have been wanting to get for a while. Since I had the Starlight Xpress (SX) filter wheel I decided to get the Starlight version of the OAG. The SX filter wheel is recessed a bit and the OAG is machined to fit perfectly onto the filter wheel. I just removed my M42 T-thread fitting from the filter wheel and installed the OAG using the supplied screws and then installed the M42 fitting onto the OAG.

I quickly noticed a problem. This configuration would be just fine with a CCD camera with a small sensor and a filter wheel using 1.25" filters, but placing the prism far enough into the light path to work properly was covering up too much of the filter and quite probably my cameras sensor. To fix this I ordered a Starlight Xpress M48 filter wheel adapter. They offer these adapters in many sizes including M54, SCT, and others.

It was tough getting a shot of the prism with the Telecompressor installed but maybe you can make out how I currently have the prism in the light path. I should have removed the Telecompressor for this image. Everything seems to be working just fine with it adjusted like this.


It was a couple weeks before I could try the new OAG out, but it wasnt because of the weather. Anyone who owns the QHY5L-II camera and is considering this OAG should know that it will NOT reach focus as it comes. The OAG comes with c-mount threads and I could not get the camera far enough in to reach focus. This QHY camera comes with a 10mm thick C-mount thread and the camera body has 1.25" filter threads. I had to order a 5mm thick CS-mount and with this I was able to get the camera to focus with the OAG. I got the CS mount from Astrofactors and I believe it was about $15. Here is a picture showing the C and CS mount camera adapters.

On the left is the c-mount that comes on the QHY5L-II and on the right is the cs-mount I ordered from Astrofactors.


Upon receiving the cs mount it was just a matter of getting things adjusted. If the prism isnt far enough into the light path the stars do not look good at all. I wouldnt call them egg shaped or even football shaped, they were much worse. With the stars looking like this PHD had a hard time calibrating. When I lowered the prism down the stars started to look much better and I was able to calibrate and start guiding. The stars on my PHD screen still are not round but it seems to be guiding and I hesitate to lower the prism any further into the light path.

Once you realize how things are adjusted its fairly simple to get things set. The long thumbscrew on the bottom is for adjusting the depth of the prism into the light path. The shorter thumbscrew on top is for adjusting the focus of the camera. For focusing the camera the c-mount slides up and down on the stalk of the OAG that the prism is attached to. The thumbscrew aides in getting the focus set and then there is also a 1.5mm allen head set screw that needs tightened once you have it set where it needs to be. Before you tighten down focus you can rotate the camera to the desired orientation.



The first night of testing went well although my PHD graph was not as smooth as what I was used to when I was using the 50mm mini guider. This is to be expected since I was guiding at around 1150mm instead of 160mm. I hope some further tweaking with the settings in PHD will smooth out the graph but as can be seen in this 100% crop of my test image (NGC 7380) it seems to be doing its job quite well. FWHM numbers were between 4.09 and 4.53 for the individual subs.

100% crop

One of things I like most about the OAG is that my stars do not drift at all. Flexure is no longer an issue! This image of NGC 7380 has not been cropped at all and you cannot see any stacking artifacts.


To show the problems I was having with flexure, here is the uncropped image of the Cocoon nebula, my most recent image done using the 50mm mini guidescope.

Stacking artifacts in luminance data seen to the left and bottom of image

One other thing I should mention is the backspacing with this setup. The SBIG STF-8300 camera has 17.5mm of backspacing and the SX filter wheel is an additional 29mm with the fittings on each end. By adding a short spacer I could achieve the recommended 55mm of backspacing for my MPCC (newt) and the Astro Tech 0.8X reducer/flattener. With the OAG added to the imaging train I am now out to about 60-61mm and can no longer use these correctors. The AP Telecompressor uses a lot of backspacing so I was good with it by adding an 6.4mm M48 spacer. Teleskop Service in Germany makes a field flattener with M48 threads that needs a ton of backspacing that I will need to purchase and use with my apo.

I would recommend the SX OAG to anyone with the SX filter wheel. I hope this post has been of some help to anyone considering this form of guiding. Feel free to contact me if you have any questions and I'll do my best to answer them.

Clear skies and happy imaging! :-)

Thursday, June 26, 2014

Summer is Back!!

Summer has to be my favorite time of year for astronomy. There's just nothing quite like seeing the Summer Milky Way stretching across the night sky and thinking about each tiny point of light being light years apart. The vastness of our own galaxy, let alone the universe, is just truly awe inspiring.

For astronomers, nothing says Summer quite like this shot from my Michigan friend, Joe Tocco, taken recently while visiting the Arizona desert and his friend Steven Aggas.

 
The image itself is stunning, but just as impressive to me is that this is a single 5 second shot at around f/3.5 with his Nikon D7100 SLR camera. This is a testament to the dark and transparent skies in the Arizona desert. The dobsonian in the foreground is Steven's monstrous 36 incher. I can only imagine what the views would be like through that telescope pointed at those pristine skies.

Here in Arkansas, the weather still seems to be in a Spring pattern. Lots of clouds, a little rain, then more clouds. There were a few clear nights where I was able to get out to the observatory. These were around the Full Moon and I was able to shoot through my Astrodon 5nm hydrogen alpha filter. I have been anxious to add color to at least a couple of these but I have to take the weather as it comes. This is only a tiny sample of some of the Summer targets and I'm looking forward to those clear nights that are sure to come. These were all shot with my 80mm Levenhuk triplet and SBIG STF-8300M camera set to -10 degrees Celsius.

North America and Pelican nebula in Cygnus
 
The Crescent nebula (NGC 6888) in Cygnus

Cygnus is a treasure trove. This is the area around Sadr, the central star in the northern cross.

To the south in Sagittarius is this beautiful pairing, the Trifid (M20) and Lagoon (M8) nebula.

 
To the north in Cepheus, you will find NGC 7380, the Wizard nebula
Just above the Wizard nebula in Cepheus is IC 1396, the Elephants Trunk nebula.

With so many things to see in the summer I sometimes feel rushed when I have so few precious clear nights. This is when I try to just slow down and try to take in the awesome beauty of what it is I am seeing. The enormity of it all is truly amazing.

As wonderful as some things are about Summer, it doesnt come without a price. Nothing does I suppose. I sure hope those two mosquitos bring back our neighbors beagle.

Have a happy and safe Summer everyone! :)

Wednesday, May 28, 2014

The QHY5L-II Planetary and Guide Camera

I recently purchased a QHY5L-II monochrome camera from AstroFactors of Plano, Texas. Bruce was a pleasure to deal with and he keeps a full stock of the QHY cameras and accessories.

The main reason I bought this camera was to replace the Orion StarShoot Autoguider (SSAG) as my primary guide camera for long exposure astrophotography. The chip in the QHY5L-II is a bit smaller than the one in the SSAG so I was a bit worried that it would not be the right choice for me, especially since I would like to someday go to an off-axis guider (OAG). The field of view would be much less shooting through an OAG compared to my current setup of guiding through the Orion 50mm finder/guider. However, so far I have been extremely pleased with this little camera....and I do mean little. Here is a shot of the camera next to an old Orion Explorer II 25mm 1.25" eyepiece.

Shown here with the focal ring from the Orion SSAG.

One of the big reasons I decided to go ahead and buy this camera is the high quantum efficiency (QE) rating. With the outstanding QE of 74% I am seeing many more stars compared to the old SSAG. With a chip this sensitive, I should have no problems finding a star to guide on when I make the move to an OAG.

My current method of guiding for long exposure astrophotography using the Orion 50mm finder/guider. Camera is inserted into the Orion extension tube and focal ring is set to easily return to focus. Also pictured is the ADM Vixen dovetail, v-clamps, and rings.
Another reason for making this purchase is that its an outstanding planetary camera. This camera, along with the ZWO ASI120MM (mono) and 120MC (color), seem to have taken over the planetary and solar system imaging forums as of late. These cameras use the same 1/3" Aptina MT9M034 CMOS sensor which has 1.2 million very small 3.75 micron pixels in a 1280 X 960 array for very high resolution imaging. The camera excels on planets, as well as lunar and solar imaging, with its high frame rate of 30 fps at full resolution. It is also capable of up to 200 fps at lower resolution. With my limited abilities with planetary imaging it will be a long time before I'll outgrow this camera. I think there might be better cameras out there, but you'd be hard pressed to find a better value. Before looking at my first attempts at planetary imaging with this camera, please take a look at this link to see what it is capable of in the hands of a more experienced user. Some have even used it for deep sky imaging of small planetary nebula! http://qhyccd.com/en/left/page3/qhy5-ii-series/

My first night using this camera was as an autoguider. It performed as expected and I was able to collect 4.8 hours of LRGB data on the Iris nebula (NGC 7023). I decided to do this with the 80mm apo at f/4.8 for a wide field shot. Main imaging camera was my SBIG STF-8300M and filters were the Astrodon Gen 2 E-series LRGB. I tried this target three different times last year with my DSLR but the heat was too much for the uncooled sensor to overcome. It turned out with fairly low noise levels this time with the new camera set to -15*C.



Since this image of the Iris nebula the weather here has been awful for astronomy. There have been a few nights though with party cloudy skies. The nice thing about planetary imaging is you can shoot about 1500 frames in about 1 minute. This, I thought, would be a perfect time to try my hand at planetary imaging!

QHY5L-II in the C8. Not shown in this picture is the 2X barlow lens that works well for solar system imaging with this setup.
For these images I used Registax 6 and had it use the best 500 frames. Jupiter and Mars were done with a 10" Meade SCT at f/10. A few nights later Saturn was done using a Celestron 8" SCT at f/20 with a 2X barlow.






Yes, more practice is needed. But it is a lot of fun and these were all done with about 1 minute each of sky time. ZWO sells a 1.25" LRGB filter set ($88) and a 5 position manual filter wheel ($88). I will likely get these to have for planetary imaging since I'd rather not take my SBIG camera off of my Starlight Xpress filter wheel. The Astrodon filters are quite expensive and I just dont want to take any chances of getting dust on them. I might even try using the QHY some evening to image some of the small planetary nebula since the Orion SSAG still works and can be used to guide.

I am hoping the clouds will part soon so I'll be able to get back to my true passion of deep sky imaging. But it sure is nice to have options, even on those mostly cloudy nights! :)

Monday, April 21, 2014

Sequence Generator Pro & Elbrus

Although I am just getting familiar with this pair, I think it will be a terrific combo for my imaging. Sequence Generator Pro (SGP) is simply an outstanding image capture program with a down to Earth price. I have just begun exploring its capabilities and already find that it is well worth the $99 price tag. Lets touch on a few of the things it can do.



The sequencing engine can control a large variety of DSLR and CCD cameras as well as several different filter wheels. I was able to download the ASCOM driver for my Starlight Xpress filter wheel from the SX website and easily install it in SGP for full control of my electronic filter wheel. You can type in any variety of targets or events. One event consist of your choice of a Light, Dark, Flat, or Bias frame as well as your selected filter, exposure time, binning, and number of frames. You can set up a large number of events and have it either finish one event before going to the next one or you can have it rotate through the events.

With the powerful Auto Focus feature I am now wanting to invest in an automated focuser to keep things focused spot-on for the entire night. SGP will measure the HFR (Half Flux Radius) of the stars and keep your scope focused without needing to slew off target to find a suitable star to re-focus when the temperture drops. Just start the evening in good focus and Auto Focus will take care of the rest. With the Flexible Focusing Patterns feature you can define patterns using time, temp, filter changes, or frame intervals to keep your images sharply focused when the temperature drops by as little as 1 degree.



SGP also has an Automated Meridian Flip feature. When used with PHD guiding and Elbrus plate-solving, SGP will automatically stop the guiding, flip the mount, re-center your target within pixels, restart the guiding and then continue your imaging sequence. I have yet to try this function but many have commented about how great it is. Once I become more familiar with Elbrus and do some wire management on my mount I will feel comfortable using this. The last thing I want now is for a wire to get caught while the mount if flipping meridian unattended. I am sure I will love this once everything is lined out, as no operator assistance is required!




SGP also has a Framing and Mosaic Wizard that is a $39 add-on. I am currently using the 45 day free trial but I will certainly be purchasing this soon. I have only used the Framing so far and it works great. Simply right click where you want the image centered and select "center here". SGP directs the mount and places your target right in the center. I have only used this a few times so far but it has worked perfectly for me every time. I'm looking forward to trying out the Mosaic Wizard sometime soon.



The Flats Calibration Wizard has been extremely useful. With my SBIG STF-8300M the target Mean Value for my flats is 30,000 ADU. I just enter this value as the target and select +/- 500 ADU as my tolerance value and it computes the exposure time needed for each filter. This has made quick work of acquiring flat frames as opposed to my previous trial and error method!



SGP supports Apogee, SBIG, QSI, FLI, Starlight Xpress, and Atik CCD cameras and filter wheels as well as Canon and Nikon DSLR cameras.

This is only a small sample of what SGP is capable of. It has excellent camera control features where you can enter the desired sensor temp and will cool down and warm up your sensor in a user defined time frame. It is also capable of controlling your mount with dithering and can control PHD, MetaGuide, and Astroart autoguiders. Frame & Focus, and many other features. I encourage anyone looking for a program like this to check out Sequence Generator Pro at http://mainsequencesoftware.com/Products/SGPro.

Elbrus is a free telescope pointing program. It uses plate solving to tell exactly where the telescope is pointed in the night sky by analyzing stars from an image and calculating the exact coordinates. The first night I used this I had the scope pointed toward M109 and told the mount to go to M51. I forgot to check "slew to" on the user interface and it took an image around the area of M109, figured out where it was after a few seconds, and then slewed the telescope to M51. Since I have started using Elbrus I have not had to hibernate my mount and I have not done anymore go-to alignments. I can now re-balance or switch out to different telescopes and not have to worry or fuss with doing a goto alignment anymore. This has made things much easier. I now just align my marks on RA and DEC at the beginning of the night and tell the mount to slew to a target. The program will then take a 5 second exposure of the stars and know exactly where it is at and move the mount to where I am wanting it to be.



It is a wonderful program that I am just beginning to explore. It has failed on me a few times but that could be due more to user error than anything else. Astrometry.net is a similar free program that I may try out sometime to use as a backup when I get things all set up. PinPoint is another plate-solver that is supposed to be very good but it cost $150. I will try Elbrus and Astrometry first because several people are reporting good success rates with these programs.

With SGP and Elbrus working together I can see myself getting a lot more imaging done in the near future. I will be able to punch in an imaging sequence on one target, and when it finishes that have it slew to, center, and start imaging another target. The best part of this is it will be working while I am indoors getting some much needed rest! I will be able to walk out to the observatory in the morning and get the data it has collected for me during the night. Well, at least this is the plan. I think with a little more time to get familiar with the programs it should become a reality sooner rather than later.

Tuesday, March 25, 2014

Lets Focus

Achieving sharp focus is an extremely important goal to every astrophotographer. All those "faint fuzzies" you have seen in your telescopes eyepiece can come to life and have depth of field when "seen" through a camera if you have proper framing and sharp focus. Even the best and most expensive telescope and camera combos wont perform to their full potential without the best possible focus. Polar aligning your mount and having good guiding also figure into the equation, but today lets talk about focus.

My first images were done with a DSLR and I used the FWHM (Full Width Half Maximum) feature in BackyardEOS for focusing. This worked well for the most part but it was still difficult on some nights getting the focus just right. FWHM is a numeric interpretation of the size of a star. This number comprises of two measurements; Full Width simply means that the full diameter of the star is used, and Half Maximum is a measure of the distance from the center of the star at which the brightness level decreases to half the level value at the center. FWHM seeks to provide an empirical method of achieving focus but because of changes in the "seeing", it is not always easy to use.

HFD (Half Flux Diameter) is a similar method of focusing. This is a feature included in the program Sequence Generator Pro (SGP). I've been using SGP since I made the switch from the DSLR to the STF-8300M CCD camera. HFD is the pixel diameter of a star in which half the energy of the star is contained. This value is similar to that of FWHM but is considered to be more reliable especially in conditions of poor seeing. Still, it has its flaws and I wanted something more precise.

I had been hearing of people using focusing mask, or Bahtinov mask. These havent been around that long but seem to have made quite a splash in the astrophotography community. In 2008, Pavel Bahtinov, a Russian amateur telescope maker and astronomer, published an ingenious new way to easily focus your DSLR camera, webcam or CCD camera for astrophotography. The method is simple, very intuitive, and the device has universally been named after the inventor: The Bahtinov Mask. They work by producing a distinctive 'diffraction pattern' in a similar manner to the way a four vane secondary mirror spider vane on a Newtonian reflector produces a four pronged star or "spikes". However, the unique design of the Bahtinov Mask produces a bright image with a diffraction pattern forming a long cross comprised of two intersecting lines and a third line that moves across the center of the cross as the telescope is adjusted in and out of focus. Correct focus is achieved when the center line fits exactly in the center of the cross. At a cost of ~$20-$30 I sure didnt have much to lose so I decided to try them.

I decided on the adjustable version from Farpoint Astro. I found what I was looking for at Agena Astro and ordered the FP400 for my 80mm Levenhuk triplet. This mask is adjustable from 2.5" to 4.5". I also placed an order for the FP404 for my 8" Levenhuk RC which is adjustable from 8.5" to 10.5" (outside diameter).

Bahtinov focus mask on 8" RC

   
Adjustable focus mask that I use for my 80mm apo


                                                                             
Example of perfect focus using the Bahtinov focus mask.

I have to say that these things simply just work. They are simple to use, cost very little, and I can now quickly achieve the best focus possible. So if you are having problems getting a sharp focus, grab one (or two) of these. I think they are something every astrophotographer should have in his or her toolbox. Makes me wonder now how I ever got by without one! I feel much more confident now that my images are focused as well as they can possibly be in any seeing conditions. Happy focusing!

Monday, February 17, 2014

New Camera!

I recently bought a few things that were on the wish list in my last post. I now have the SBIG STF-8300M camera, Starlight Xpress 7 position 36mm USB electronic filter wheel, and a new Astrodon 5nm hydrogen alpha filter. After a long wait for the clouds to part I was able to get out and capture a few images with the new equipment.

SBIG STF-8300M and Starlight Xpress 36mm 7 position electronic filter wheel set up with the Astro Physics CCDT67 Telecompressor ready for imaging with the Levenhuk carbon fiber RC telescope.
I decided I would switch from the RC to the Levenhuk 80mm triplet apo for the initial test images. I had to order an 8mm T2 spacer from Agena Astro to get the spacing within half a mm of the recommended 55mm backspacing for the Astro Tech 0.8X reducer/flattener.

The first night out I decided I would target the Seagull nebula (IC 2177). Clouds ended my session earlier than I would have liked but I managed to get in 1 1/2 hrs (9X600sec) on the Seagull and was impressed with what I was able to get with the new equipment. This was also roughly 30 degrees away from a near full Moon.



Compare this to a recent image taken with the same scope on a dark night with my modified Canon DSLR and you will notice a lot more detail from my new CCD with the H-alpha filter.


I had tried imaging the Cone nebula (NGC 2264) before with the DSLR but just could not see anything. I decided I would aim for that a couple night later. This image is 14X600 seconds.


After the Cone moved past meridian, I slewed and refocused the telescope on the Rosette nebula for 14 more shots of 600 seconds.


All of these were shot with the camera sensor set to -15 degrees Celsius. It was very nice to be able to set my temp and then also capture my darks, flats, and bias frames at the same temp. The sensor was kept at a stable temp and varied less than 1/2 a degree. All shots were from -14.8*C to -15.2*C. I captured 24 darks, 30 flats, and 100 bias frames to stack with these images.

There was a problem though. If you will look to the left side of the pictures you might notice a few vertical lines. I was stumped as to why this was but was able to trace it back to my dark frames. I took a set of 12 darks earlier that were fine but my second set of 12 is were the problem came from. The unstretched dark frame appeared to be fine but when I pulled one into Photoshop and did a couple aggressive stretches using levels and curves this is what I found. It fit exactly what I was seeing in my finished images.


The second set of darks were done during the daytime and I thought it could be from light seeping in somewhere. A couple other guys with these cameras however are also reporting these issues so I will just need to keep an eye on things. I will delete this second set of darks and re-take a new set. Hopefully I will then be good to go.

Aside from the issue stated here I am very happy with the new setup and I'm anxious to add the Astrodon LRGB filters as well as the OIII and SII narrowband filters and start getting some color. I will have to be content with what I have for a while longer but I'm excited about the possibilities.

For the full resolution view of these pictures please visit my gallery on Astrobin. http://www.astrobin.com/users/rflinn68/

Thursday, January 2, 2014

Year Ending Images

2013 was a great year for imaging at Little Piney Observatory. We learned a lot, and also had some failures. Most of the failures occurred on the hot Summer nights. Having just started serious imaging in November of 2012, it was our first experience with a hot camera sensor. Let me just say that it was then that I started saving up for a nice CCD camera with cooling capabilities.

Not knowing much at all about CCD astronomy cameras at the time,  I only knew that I wanted one that was capable of keeping the sensor cool. The images with my modified Canon T3 (1100D) seemed to be ok with a sensor temp up to about 27 degrees C. The difference between 27*C and 32*C was enormous.

I have since decided to purchase the SBIG STF-8300M monochrome camera which should greatly improve my images, especially during the Summer months. It is capable of cooling the CCD sensor to -40 degrees C from ambient temp with set point cooling which makes matching dark frames much easier. I hope to have my new camera along with the Starlight Xpress USB powered 7 position 36mm filter wheel by early next month. I plan to start out with an Astrodon 5nm hydrogen alpha filter and gradually fill the filter wheel with Astrodon Tru-Balance E-series LRGB colored filters and the Astrodon 3nm OIII and SII narrowband filters. I am really looking forward to my journey into monochrome CCD imaging.

The forecast for the remainder of the current dark window looks pretty bad so the recent images I was able to get could very well be my final astro images with my DSLR camera. Gary Honis modified my Canon back in March with the Baader UV/IR filter and it has served me well for all but the hot summer nights. I was thankful for the opportunity to get out to the observatory for a few evenings and capture these new images. Most are HII regions, which I'm sure will make me appreciate the new camera and h-alpha filter even more once I have them up and running in the observatory and re-visit these targets.

The Monkey Head nebula (NGC 2174), 33X300 seconds (2.8 hrs)

The Soul nebula (IC 1848), 31X300 seconds (2.6 hrs)

The Rosette nebula (NGC 2246), 36X300 seconds (3 hrs)

The Flaming Star nebula (IC 405), 43X300 seconds (3.6 hrs)


The Tadpoles (IC 410), 47X300 seconds (3.9 hrs)

The Seagull nebula (IC 2177), 23X300 seconds (1.9 hrs)

The Witch Head nebula (IC 2118), 41X300 seconds (3.4 hrs)

I was able to get these from the nights of Dec 27th through Dec 31th. They were all shot with the Levenhuk 80mm triplet using the Astro Tech 0.8X reducer/flattener. The Canon DSLR was set at ISO 800 and Auto White Balance was used on all the HII nebula, Custom White Balance (White Paper) was used on the reflection nebula (Witch Head). Please see my Astrobin gallery for the full resolution pictures. http://www.astrobin.com/users/rflinn68/

It was a good ending to a very good year. I hope 2014 is every bit as rewarding as my first year in this wonderful hobby has been.