Friday, November 28, 2014

New Arrivals at LPO

There has been a changing of the guard recently, on a couple fronts, at Little Piney Observatory.

Those of you that have been following my progress know that the 800mm focal length AT8IN was sold some time ago, and I have since been saving up and looking for a nice apo to replace it. I liked the field of view I got with that scope using the DSLR. The STF-8300M has a smaller chip than the DSLR, so I was looking for a triplet in the 600-700mm focal length range that would produce a similar FOV.

After much research, I decided to purchase the TS Photoline 107mm f/6.5 Super-Apo with 3" CNC focuser and modular carbon fiber tube, from Teleskop Service in Germany. APM offers this exact scope in a metal tube version.

The optics in the scope are said to be very close to the famous LZOS. It is an air-spaced triplet with an FPL-53 element. The interior of the scope and dew shield is lined with a black felt and seems to provide very high contrast views and images.

The first night out with it was a quick eye test to check collimation and do some observing. As expected, the color correction was excellent and viewing with an Explore Scientific 82 degree 8.8mm eyepiece provided extremely high contrast views even when pointed towards a rather large and bright Moon. It can best be described as the often stated, "shimmering diamonds on a black velvet background." I am very impressed with the views this scope provides, and look forward to pushing the magnification for some planetary observing soon.

The scope did not arrive without some anxious moments. The big box it came in was leaking shipping peanuts as I carried it into the house. It was obviously not treated very well by UPS.

Fortunately, it was packed very well and had a smaller box with a nice case inside that protected the scope.

Now the worst part of the whole ordeal. I pulled the scope out of the case and removed the dust cap. When I pulled out the dew shield I saw something that horrified me. I immediately thought that these two screws had been bouncing off the lens during its travel across the Atlantic!! Thankfully, when the dew shield is closed it seals off everything from the optics.

These are two of the three screws that hold the lens cell to the optical tube. Not really something you want to see when you pull out a dew shield. I removed the dew shield and put the screws back on. After getting all three screws snugged up fairly tight everything seemed to be fine.

It was a while before the clouds allowed me to get in some imaging with the scope, but the first night out with it gave me the results I was looking for. The only thing is the carbon fiber tube does not behave like my carbon fiber RC, in that it does not keep its focus as well when the temps drop off at night. I suspect this is because the tube has two 60mm long extensions that have metal threads. These threads will expand in the heat and contract in the cold which changes focus. My FWHM (Full Width Half Maximum) started out in the low 4's and as each frame clicked off the stars grew to a FWHM in the mid 7's after eight 20 min subs. I refocused and frames 9-13 remained in the 4.01 to 4.28 range. Last night I captured some RGB of IC 405, the Flaming Star nebula, and the FWHM was as low as 3.80 and was never higher than 4.61 for the entire night. Since the 3" focuser appears to be pretty stout, I think I will keep it and remedy this problem by getting a Rigel nStep stepper motor with temp sensor and automate my focusing for this scope.

Here's what I managed with the camera the first night out with it. This includes all thirteen of the 20 minute hydrogen alpha subs. Soon I will be getting some new H-alpha data and will get rid of frames 3-8 which should make for a better looking image. I'll be adding RGB and possibly some OIII soon.

The other new addition is the Stellarvue SV60EDS. I decided to sell my trusty Levenhuk 80mm f/6 and try out this very small 60mm f/5.5 scope. The 330mm focal length gives me a much wider FOV compared to the 480mm focal length of the 80mm scope. TS even makes a 0.79X reducer/flattener that would work for me and reduce the focal length to 260mm and focal ratio to f/4.3 for an ultra wide fov.

I have yet to find the sweet spot for this scope using the TSFlat2 field flattener. I am not at all happy with my corners, but the color correction seems good and I love the field of view. This is a test shot of the Rosette nebula, two 30 minute subs with no darks, no flats, and no bias frames.

Hopefully I can get the spacing figured out for this scope and get some nice widefield shots. If I cant get the spacing right for the TSFlat2, I might purchase the TS 4-element 0.79X reducer/flattener. This corrector says the spacing needs to be 70mm for up to 350mm focal length. It should be very close with the 330mm fl Stellarvue.

I'm looking forward to using these two scopes a lot more in the near future. Hopefully the weather here will allow this. Although I'm not completely sold yet on the SV60, I plan on keeping the TS 107mm for years to come.

Happy Holidays!

Friday, October 31, 2014

Starizona Pier Adapter and Baader Helical Focuser

With the sale of my CGEM DX mount, I needed to find a new pier adapter for my new Atlas Pro mount. I had been using the adapter from the top of my CGEM DX tripod.

Starizona offers a pier adapter called the CGEM Pier Adapter kit. Since my Atlas Pro worked just fine with my CGEM tripod adapter, I knew this would work fine with the Atlas. It likely will also work on a few other mounts as well, but I'm not able to verify this.




So far this seems to be working out great for mounting the Atlas Pro to the pier. I may be putting a little thicker top plate on, that the pier adapter is sitting on, but its working fine as it is so I'm in no big hurry to do that.

The other upgrade I've been wanting to do for a while is find a solution for focusing my guide camera on the Starlight Xpress OAG. It uses a thumbscrew and an allen set screw. You loosen these and slide the camera up and down the stalk to focus the camera and then lock these two down. It doesnt slide very smoothly and its quite difficult to get the camera focused.

The OAG uses a male C-mount and I ended up getting this c-mount to t-thread adapter from ScopeStuff and the Baader helical focuser from Adorama. Agena Astro was out of stock on this item at the time but I was able to find one at Adorama for the same price. Both places are a pleasure to do business with.

This worked out great and makes focusing the QHY5L-II guide camera much easier. The focuser has an internal compression ring and three thumbscrews for clamping the camera in place and also includes a focus lock screw.




I'm enjoying the new upgrades as small as they may seem. Anything that makes this hobby a little easier gets a big thumbs up from me! I'm looking forward to the coming weeks here at Little Piney Observatory. I have some bigger plans in the works so stay tuned. :)


Thursday, September 25, 2014

EQASCOM Polar Scope Tool



This is really just an update from my post a few days ago about the Atlas Pro AZ/EQ-G mount and the new software we've been trying out to get everything up and running. I did not mention Alignmaster because we simply could not get it to work correctly. I'm still not sure if this is because of user error or not but we have found something else that seems to work great.

This method does require that you have a view of Polaris (for Northern Hemisphere users). When using a polar scope it is very important to place the RA axis of the mount precisely where Cassiopeia and/or the Big Dipper appears in the sky. This can be really difficult to judge sometimes and usually it is just a guess. EQASCOM and Chris Shillito of the EQMOD Project has come up with a simple solution.

I wont go through the routine here, but will say it is very easy and it just works. After going through this simple procedure the guiding graph in PHD2 looked much improved compared to just eyeballing it. It seems to be very precise. Here's a screenshot of the graph after aligning the mount with this method.


Here's another after making a few small adjustments. The mount only required that very small corrections be issued from PHD2.


These were done with the 80mm f/6 apo, the next night out we tried guiding the 8RC at 1600mm focal length and it performed great. Looking forward to getting my camera back from SBIG and putting it all to work.

For complete details on using this method please see Chris' video.


Detailed written instructions can be found here:

http://eq-mod.sourceforge.net/docs/PolarScopeAlignment.pdf


Monday, September 22, 2014

Atlas Pro AZ/EQ-G

I managed to get several images with the CGEM DX mount over the last 2 1/2 years. Some pretty good, some not so good. It was just very unpredictable, and I started saving up some money and sold the AT8IN telescope to help fund a new mount.

There were several that I had my eye on. The new iOptron CEM60 EC seemed to be a very nice mount. The Losmandy G11 has been trusted for years and has recently been refined with the release of the Gemini 2 hand controller. Both of these mounts will carry a maximum payload of 60 lbs and looked appealing. The new Orion HDX110, which is the Skywatcher EQ8 with the Orion name, also looked very nice with its capabilities of handling up to 110 lbs of weight.

There are a few things I'd still like to buy for my astrophotography hobby. I still need to get the Astrodon OIII and SII narrowband filters. I would also like to automate my focusing with motorized Moonlite focusers on my telescopes. And I would like a nice 110-130mm apo triplet to have for visual use, as well as fill the void in my imaging line of scopes left from selling the AT8IN. Its a pretty big jump from the 480mm focal length of the 80mm triplet up to the RC's 1150mm focal length using the CCDT67 Telecompressor. So I'd really like something in the 700-800mm range.

After weighing my mount options with my wants/needs, I decided to settle for a smaller mount. The new Atlas Pro shares a few features of its big brother, the HDX110. They both use the same Altitude adjuster that is much smoother than most mounts on the market. They both use belt driven stepper motors with dual encoders. And they both use closed-loop electronics which allows you to manually move the scope, or rebalance, without it loosing its alignment. The Atlas Pro AZ/EQ-G it would be!

I ordered the new mount from Orion and it arrived in two boxes about a week later. When I set up my pier last year I removed the mount adapter from the top of my CGEM DX tripod and fabricated a way to fasten it to my pier plate. I was hoping it would work with my new mount. The metal post for adjusting azimuth was too long for the Atlas Pro mount, but it was as simple as removing the CGEM DX post and screwing in the one that came on my Atlas Pro tripod. It fits!


This picture shows the mount set up for my 80mm triplet. For larger scopes, the mount also comes with a counterweight bar extension and another 11 lb counterweight.


 The mount is so quiet when slewing! I just had to remove the cover to check out the stepper motors and drive belts. This is a really nice system and much better than gear-to-gear in my opinion. In addition to being quieter the backlash is also significantly reduced or eliminated. There is always some backlash in any gear-to-gear system.


This is a close up of the "Captain's Wheel" DEC clutch. The small t-bolt under it allows the counterweight shaft to retract up inside of the mount for easy transporting and storing.


Here is the RA clutch and just below it is the illuminated polar scope. The brightness of the illuminated scope can be adjusted with the hand controller.


This is the adjustment for altitude with the handle retracted. It is much smoother than the other equatorial mounts I have used. Below it is shown with handle out ready for adjustment.


I have not been able to really use the scope yet for imaging, but I am confident that this will be an excellent mount for astrophotography. The very first night, we did a rough polar alignment using the polar scope and did a little autoguiding and it performed great. Here is the PHD graph with no adjustment of the PHD2 settings and the rough polar alignment. I am sure with a more refined polar alignment and some fine tuning in PHD this will get even better.


One big reason I wanted to go with this mount is that it is supported by the EQMOD Project. I have read great things about EQMOD and EQASCOM and wanted this program for controlling the mount/telescope. It really is a well thought out program with excellent capabilities. I am still trying to learn more about it but everything so far has been positive. I will report in more detail about EQASCOM as soon as I feel comfortable using it and learn more about it. Please check into it yourself to see if your mount is supported. If so, I think you will really like the program. I did purchase the recommended interface cable from Shoestring Astronomy for connecting the mount to the computer. For the Atlas Pro AZ/EQ-G this cable is the USB2EQ5. For regular Atlas owners this would be the USB2EQ6 interface cable.


For aligning the mount for goto you can make a pointing model using several stars. Usually just a star to the west and one to the east will be good enough for casual goto performance. This is great for observing but with Elbrus plate-solving software its not really needed at all for imaging.


I should also mention another piece of software that is very important. With the interface cable from Shoestring Astronomy, you no longer use the hand controller. EQASCOM controls your mount but you'll need something else if you want goto capabilities. Stellarium is great for this but I found that it was too much of a memory hog for my old desktop that I have in the observatory. I found a free program that others are using called Cartes du Ciel. So far it has worked great and seems to be a nice program.



Just select a point on the sky chart to get coordinates for your plate solving software or select slew for goto. With tracking enabled it will track where your scope is pointing on the sky chart.

By this time next month I hope to have a few images under my belt using the new set up. Hopefully by then I can report a lot more on the new software and the performance of the new mount. I believe that the Atlas Pro AZ/EQ-G will be a wonderful addition at Little Piney Observatory. Clear skies everyone!

Sunday, August 17, 2014

Improving Corners and Homemade Dew Shields

This months post is a follow up to last months review of the Starlight Xpress off-axis guider. Adding the OAG in the imaging train needed some recalculating of the spacing for the Astro Physics CCDT67 Telecompressor that I use with my RC telescope. Most all scopes require some sort of corrector to make the stars in the corners of the image round. I noticed I had some serious problems but I had also experienced problems with my focuser and had blamed the aberrations in the corners on slop in the focuser. I took the focuser apart and found the problem and fixed it. I expected things to be well again but that was not the case at all.

PixInsight has a really neat tool under 'Script' in 'Image Analysis' called Aberration Inspector. It divides the image up into sections and will show in good detail how your stars look throughout the image. Here's what aberration inspector showed on my recent Bubble Nebula image.


The lower corners show extreme curvature issues and the top is so bad that the stars appear to be badly out of focus. Things are nice and tight in the center. Since the focuser was now fixed it was time to look elsewhere. I decided to careful measure my backspacing again and found that it was less than what it was previously before I added the OAG.

I mentioned in last months post that I went from M42 adapters to M48. Agena Astro has a limited selection of these spacers and I had the shortest one already with the 1/4" (6.4mm) spacer. The next step up is a 1/2" spacer. I really didnt think that I needed that much more, but at just $16.95 I decided to give it a try. It seems that this has again put things in the sweet spot for the Telecompressor. I decided to test it on a large Open Cluster and chose the Double Cluster in the constellation Cassiopeia. Here's what PixInsight's Aberration Inspector showed after increasing the spacing.



The stars in the corners are clearly much better than before. I still have work to do however as I ran across some more issues. The prism of the OAG was too far into the light path and is causing some weird diffraction patterns on the stars to the right side. I think this should be easily fixed though by simply raising the prism up a little more.

With the issue of the corner stars fixed I decided to tackle another problem I have had for a while. Dew is a huge problem here in Arkansas and a while back I had invested in a secondary dew heater for the RC scope. The problem of dew was fixed but I have not been happy with the shapes of my stars since adding the heater. The secondary dew heater was just slightly larger than the secondary holder on my 8" RC leaving the edges of the heater adding to the secondary obstruction. The edges of the heater are not particularly smooth and this, combined with the wires ran across the spider vanes left a mess of the diffraction around my stars. I put up with it as long as I could and finally peeled the heater off and looked for other solutions.

Typical Diffraction pattern with secondary dew heater

I have made a few of my own dew shields. In fact, I have never bought a dew shield before. I think I found this on the website for the DewBuster heater controllers and I must say that they work great. I went to the local Lowes hardware store and bought a roll of Reflectix insulation, a can of 3M Super 77 multipurpose adhesive, a box of the heavy duty velcro, and a can of flat black spray paint. Using these items it is quick and simple way to make a homemade dew shield.

Reflectix Insulation
Start by wrapping the Reflectix around the OTA and cut it at the desired width. Next, just notch around any dovetails you might have. For my RC, I have an ADM Losmandy style on the bottom and a Vixen style on top. Making your own dew shield likely makes for a much better fit if you have custom accessories added. The Reflectix is shiny on both sides and the inside of the shield needs to be painted flat black. After the shield has been test fit and cut as desired, the inside of the shield needs to be sprayed with the 3M glue. This acts as a primer and allows the paint to stick. Without this step the paint will not stick to the Reflectix material.




After the 3M adhesive has dried you can then spray the flat black paint. Once it has dried you can apply the velcro in the desired locations and you are finished. Presto! A dew shield! I added the soft part of the velcro along the back of the shield to protect the finish of the scope.


I also had a heater strip for my C8 telescope and decided to also add it just past the halfway point towards the back end of the OTA. I wasnt sure how this would work with my scope having a carbon fiber tube but after two nights out the mirrors have remained clear of dew. The dew shield has been soaking wet on both nights but the scope has been dry both inside and out!

I will say that I believe the secondary dew heater that I have will work fine on the 10" and larger scopes. The heater is just a little bit too big for the 8" RC's. Where the wires come out of the heater you simply can not turn them sharp enough to keep them out of the light path, so this was another source of diffraction issues.



The diffraction pattern around the stars is much improved without the secondary dew heater. Though this shows other issues with the tracking/guiding, diffraction is no longer a mess. Just last night my wife and I started trying out ASCOM pulse guiding and it seems to be doing a better job than guiding through the ST-4 port on the mount. Maybe this will be a future post from Little Piney Observatory. One thing I have learned since I started imaging, is there is always something new to learn in this hobby!

Clear Skies!

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! :)