rodrigol

Follow-up: I discovered play on the RA axis and a lot of backlash on the mount, which I set out to fix. Sadly, I got a vout of kidneys stones that have taken 4 weeks to get sorted. The RA play has been sorted by careful adjustment of the wormgear hex screws and I've also replaced the cgem saddle with the human friendly one from ATM. I've now got a very smoothly balanced mount with a much easier means of balancing the OTA. Only the weather is standing between my setup and the next picture.

@Graeme, many thanks for the picture and apologies as well for the time it took to respond. I've been out of action due to kidney stones, which I'm not going to go into here. I don't remember where now, but I did find info on where the FR was supposed to go in the first place. In front of the camera, as you say, and further away if one want a different FR ratio. I've been having tracking issues, which I've tracked down to a loose RA axis and which resulted in horrible backlash. Rather than attempting to compensate for that I decided to adjust the worm gears. I now have a very smoothly balanced and backlash-less mount. I also changed the saddle for the ATM one, which is very forgiving when balancing and has human friendly knobs. The original celestron cgem saddle is not designed for people with long hands and fingers, like me, and is in fact a bit dangerous. My next challenge is to fit a 2"filter to the OT. Many thanks for your support!!! R:)

HI, Thanks for the comments 😀 The guiding is proving challenging but I hope to eventually get there. I'm just praying there is nothing wrong with the mount and that careful calibration of the guiding setup in PDH2 will deal with most or all of the gremlins. One piece of info that is eluding me is the correct FL to input in PHD2. I'm using 1960mm , which is the theoretical value many have calculated for the optical train I have, but that does not include the OAG (does it matter?). The QHY5L-II has now a 0.5 FR at 28mm which really make a difference when getting hold of guide stars. So, I've trying around this value. BTW, my PHD2 mx values are set at 5000 and the RA and DEC agr are at 100. This seems to get guiding to be stable for some of the 60s frames, but not for the majority of frames. To make sure the mount is 'ok', I will try ST4 guiding as soon as possible.

Below is M13 taken with my experimental rig: C11 Edge HD + 0.7 FR + Celestron OAG w/ QHY5L-IIM + 0.5 FR. Processed with DSS and PI. Calibrations frames from my library. The main camera is an ASI1600MC (not Pro/Cooled). 30 x 60s subs of which only 8 has nice round stars. The rest where eggs, yeasty-like shapes nonsense. I tried to make some sense of these but knowing they would spoil the core of M13 did not motivate me to attempt any correction. The mount seems to track relatively well and the guide setup /w the 0.5 FR is sensitive and always seems to find stars to guide on. Without this FR there is a different and frustrating story to tell. But my issue is that every once in a while, the star goes for a couple of seconds, or the mount slews/drifts (according to PHD2) when it is actually not. I've got to try normal ST4 guiding to compare. Oh! And I know that the PI deconvolution is a tad overdone 😐 As always comments are more than welcome 🙂

Hi Rodd, Thanks for looking! You are right, the stars are a bit mishshaped. A bad tracking frame got through and into the stack. Focus could be a bit off as well. I didn't refocus after an almost full RA revolution. First frames looked good before I left the session carry on its own. I'm going to see if I can correct the stack and try smart scale sharpening as you suggest. Thanks for the support, R.

M57 in widefield with a C11 EDGE HD + 0.7 FR + ASI1600MC. 60s x 9 with calibrations frames from my library. Stacked on DSS and processed in PI. I did struggled to get the colours right and you can see this in the neighboring stars. Enjoy and as always comments are welcome! R:)

I've posted my first image of M27 taken with the rig as described above (https://stargazerslounge.com/topic/340204-m27-dumbbell-first-oag/). I'm very happy with the results and looking forwards to more clear skies (but work has taken me away from y scope 😞 ). If anyone is using a 0.5 FR with their guidecam and OAG, can you let me know about how this one is placed in the guidecam imaging train? I suspect it is in front of the camera but when I tried I was not able to get focus at all. Much appreciated! R:)

Hi Richard, Thank you! Good point about debayering and could explain what is going on. The images where taken as FITS and I didn't use PI to process them where I could have selected up-bottom FITS. I ended up using DSS and testing all the generic debayer patterns until I got the colours right 🙂 R:)

My first image using a C11 Edge HD with 0.7 reducer and Celestron's OAG. Main camera is ASI1600MC. Guide camera is QHY5L-IIM. I only did 50 x 30s Lights and used master darks, flats and bias from a new library. I recently added a pier to my obsy and have been working on getting the scope and assorted equipment on it into shape for the autumn and winter skies. This was a test of various components of the setup. The image is far from perfect but I'm quite happy. One mystery for me was that I had to use GRBG as the Debayer pattern to get the colors right. Comments are more than welcome! R:)

I was wondering if you could let me know about the placement of the 0.5 focal reducer? Many thanks be forehand !

That's exactly what I did! Many thanks for your advice and patience!

Just wanted to report that I nailed it! 😁 Thanks to everyone that gave me their advice and time. 😎 This community rocks! I used the moon and focused the ASI1600MC first, moved it to the field of view of the guider, and proceeded as adviced here. Indeed the fov is narrow and a reducer is a great idea! Thanks to all!

Your are right! I totally agree. I was just thinking aloud... This is where I am at the moment but not have tested. I just want to know if this seems reasonable. I've used all the spacers at my disposal for the imaging camera to get ~146mm from the reducer. And given that, I've measured the distance from the centre of the OAG to the main camera sensor (~115mm) and reproduced that from the prism to the guide camera sensor. Does this make sense now?

Hmmm... Maybe my issue is that I'm using the wrong m48 spacer between the oag and the main camera. I'm using the 11.55 spacer. I'll try without...

Hi GraemeH, Many thanks! You've got some nice output from your EdgeHD in astrobin! Congrats!

Hi GraemeH, Would you mind posting a picture of your setup? I've got the C11 edge focal reducer in as well but don't think this is getting in the way. Thanks for the support 👍

Argh. Have lost a lot of time on the oag and don't think Ihave the right guide camera for it. OAG will go in the box until I can afford one. Thanks everyone for your patience.

Dropping the prism has improved things a lot. The ZWO 290 has a relatively small sensor so there is little to worry regarding the prism shadow. I guess it will be an issue with the DSLR. Some progress 😁

Hi Michael, Many thanks for the tips. I believe the prism is the right way (diagonal facing the camera). I'll get home later on a check the height of the prism... Again, many thanks for your advice!

Many, many thanks for the feedback. I tried again to get the setup working with a qhy5l-iim as that has a shorter Cs adaptor and is a more sensitive camera. I simply could not get to see anything to focus with on the guide camera. I may need to dissemble the oag from the scope and check the prism is low enough to capture some of the light path. It's weird because I really see nothing and I'm getting frustrated that the only way to see anything in daylight through the guider port is with a very long stack of adapters. I'll report back ASAP but first want to thank you guys for the help. You rock!

Hi Dr_Ju_Ju, Thanks for comment 🙂 Do you find the ASI 120 is a good guider cam compared to the qhy5l-ii? They are different beasts and 0Need to know in order to decide if qhy5l-ii are any good for OAG guiding. Thanks!

Thanks! It looks as if I've been adding too much when in fact I should have been using much less. Any idea if I have to remove the CS adapter from the qhy5l-ii?

I'm currently testing my new OAG with a Nikon D7200 and ZWO ASI 290 on a C11 Edge HD and I can achieve focus with both quite easily. But getting focus with the guider camera, which is a qhy5l-iic, is not working for me. I also have a qhy5l-iim, which I've yet to take out of the box. The current setup is below and consist of C11 Edge reducer+OAG large SCT adapter (https://www.celestron.com/products/large-sctedgehd-adapter-for-off-axis-guider) +OAG + T-thread spacer + main camera. I've tried with a variety of CS-C spacers and ended up managing to focus the guide camera on a relatively far away tree with 2x50mm + 3x5mm spacers giving 115mm total. But this just looks silly and is unworkable at night. Can someone please comment and point me in the right direction, please?

The latest now is below I'm now purpising a Celestron Motor Focuser, but the one I got was jammed tight. Hoping for a fix soon.

Need to see about changing rollers. I can move the roof with one hand, but would like it to be with my pinky! Some more progress below... Yes, I know my tiles are a bit wonky 😁