04Stefan07

Just going over my data I captured over 5 nights of the Rosette Nebula and have noticed some star issues between subs. See main setup in my signature (GT81). After dialing in my back focus and tilt (finally) these are at a minimum. I have less than 6% tilt and I think my back focus is almost bang on. I have attached some subs which were taken one after another and wanted to get some opinions on what my issue could be. My guiding is generally alright (around 0.4 - 0.6 RMS depending on the night) but I have noticed every now and then my DEC on PHD2 goes nuts then corrects itself. I think I may have some backlash in the mount. Also in my final stacked images which are 2x drizzled the stars look alright but I wouldn't mind trying to fix this. The image attached I have circled some reference stars and you can see they become slighly elongated.

Great image but I am looking at doing colour with my RC6. I am already imaging in narrowband using my refractor.

I wanted to start a thread with my experience using my different telescope setups. See my main imaging rig and my secondary rig configurations below. The main rig works very well with narrowband and RGB imaging (there are some minor back focus and tilt issues I am sorting out but nothing noticeable unless you zoom in on the captured images). Centre on my target and I get a plethora of stars and off I go. With the RC6 I have been having a range of issues which I will outline below. Overall weight: The RC6 setup with a guidescope is pushing upwards of 9kg, maybe 9.5kg. It's a bit of a stretch for the HEQ5 Pro in my opinion Balancing: Using a guidescope introduces extra weight on one side of the tube and throws the balance out. This is where an OAG is preferable Imaging: As I use mono for my main rig I wanted to setup the RC6 with a colour camera to obtain subs quicker (can get something decent in a night instead of 3-5 with mono) Guidescope & OAG: I have seen most people use a guidescope with an RC but I think an OAG would be a lot better. I have tried both and I can't seem to get the OAG working at all and when using the guidescope the guiding is awful. This could be due to the weight of the setup or flexure. I am using the ZWO OAG and the Orion 50mm mini guidescope. Guide camera: ASI120MM and have used a PlayerOne Neptune-M. Camera: The choice of camera I have seen is either a DSLR or a OSC Cooled camera. I am very familiar with DSLR's and cooled mono cameras in refractors but not so much in an RC telescope. I captured M42 using my Z61 refractor and 1200D which came out great. I have tried using a 1200D and a PlayerOne Uranus-C camera (which is meant to be pretty good for deep sky stuff without cooling) and again having some trouble getting them working perfectly. Questions/Solutions I am looking at upgrading my HEQ5 Pro mount next year with the iOptron HEM27 which has a payload capacity of up to 20kg with a counterweight or 13.5kg without so this may solve some of the issues I am having in regards to weight and balance Should I try use the 1200D or stick with the Player One? I am guessing with colour cameras and no filters there would be less visible stars so how do you work out if you are on target and getting crisp focus?There are more people using a DSLR online and not so much with a webcam styled camera Should I use the OAG or Guidescope? I won't be using a field flat so I am guessing I don't need to achieve 55mm back focus? I can attach the OAG with the DSLR but I have trouble focusing and finding stars. Do I need to upgrade the guidecamera to get a larger sensor?

Trying to sort out cameras and filters with my portable and deep field rig, see below for info and if anyone can offer any suggestions or advice that would be great! Rig 1 (Wide Field Rig): WO GT81 IV, ASI1600MM with filters - This is my main narrowband imaging rig, this will stay as is Rig 2 (Deep Field Rig): RC6, 1200D - Secondary rig, looking to replace with another camera? Possibly add a filter? Rig 3 (Portable Rig): Evoguide 50, 1200D - looking to replace with another camera? Possibly add a filter? I have attached my FOV which work out really well! Info: - I have 2x 1200D's, both unmodified - I have a 2" Astronomik CLS CCD filter which I recently purchase second hand - There is an opportunity to purchase a QHY8 Pro OSC - If budget allowed I would have purchased an ASI OSC cooled camera. Please don't suggest to buy a brand new OSC Questions/assumptions - Should I modify one of the 1200D's and keep the other unmodified? Can't find pricing on this and not confident enough to do it myself - If I do the above, should I have an L-Enhance or L-Extreme filter in one and a CLS in the other? - I found a t-ring adapter that Baadar make that accepts 2" filters, this might be a good purchase so I can purchase 2" filters instead of clip in's. This will allow me to use my Astronomik CLS filter with both 1200D's and allow me to purchase other 2" filters in future - How does the QHY8 Pro compare with a stock 1200D? I know its old hardware but the features that are driving me towards purchasing it is that it has cooling and doesn't require modification at all (also it can be used with rigs 2 & 3) - Optolong L-Enhance and L-Extreme. Been reading reviews on these filters and they look pretty good. Is it worth purchasing one of these and selling the Astronomik? Also heard an H-alpha filter is well worth it or a CLS light pollution, unsure which route to go. Have seen reviews and comparisons on Youtube which have helped explained what they do but this will depend if I purchase the OSC. Possible solutions - Rig 2 (Deep Field Rig) - RC6: - 1200D unmodded - 1200D modded with a filter, if so which one? - QHY8 Pro (with a filter) - Rig 3 (Portable) - Evoguide 50: - 1200D unmodded - 1200D modded with a filter, if so which one? - QHY8 Pro (with a filter) Thank you, Stefan.

Great options. I went with the 50 as it's a perfect size and I can fit it all in my case with my Star Adventurer. I purchased the Starizona field flat as it works well with a DSLR and gets better back focus. Will report once I receive and set it up!

Still get to get first light with the RC6. It's taken a bit of effort to set it up the way I want. Main issue being how back heavy it is. Will report first light once done!

Ooo a 50! Looks interesting. Don't get me wrong it was easily one of the best telescopes I have owned and captured an awesome image of M42 with it. But because I now have a GT81 it pretty much replaced the Z61. I ended up replacing the Z61 with an RC6 so I could at least get a narrower FOV.

*Ignore my signature, it needs to be updated* I no longer have the Z61 as my portable rig. Currently I have my wide FOV (GT81) and narrow FOV (RC6) as my main rigs and a solar rig. With my portable setup I use a Star Adventurer (v1), DSLR with a nifty fifty lens with a Rasberry Pi and camera for guiding which works well. I was hoping to up this a notch and the reason I am not looking at something like a Redcat 51 is that I very rarely take the portable setup with me so I can't justify spending 1.5k on that scope/lens. Also when I used to have the Z61 by the time I decked it out it got close to 5kg and there was too much to setup and configure. I was thinking maybe getting a better quality lens that has a wider FOV than the GT81 + 1600MM. Or is there a cheaper 50mm scope? Any suggestions? Thanks!

Thanks, Alan. I've got a long weekend coming up so I can spend some time building the rig. Luckily my 3D printer will come in handy. I'll report back with my findings. I've got my RC6 with my 1200D I need to setup as well!

Oh, I completely for about that! I did buy the parts for it too. Have attached the sub. frame_and_focus_1.fit

Alright, so I returned to this issue on the clear nights I have been getting (only has been a couple in the last month!). I purchased a few tilt shims which took 5 weeks to arrive but are meant to be easier to use than a tilt adapter. So far, they are so much easier to use. Every shim adds around 0.4mm back focus so I have compensated for that. Ran a few subs and I am still getting tilt but its all on the left hand side. Since the corners are reversed, I put the shim on the right hand side (looking from the back) of the camera and the tilt does not change. Is it possible there is tilt elsewhere in the imaging train? At this rate I think I will need to leave it and start imaging.

Ah yes! Luckily I didnt say 1.21 gigawatts!

Yep it is looking much better! So it looks to have been crappy focus this entire time mixed with some minor seeing conditions. I am going to have a go and building up that rig. Is there a recommended laser to use in terms of power? I hear sometimes it can damage the camera sensor. I found a 650nm 1nW Red on ebay for cheap.

Here are a few subs I took using NINA. There isn't as much tilt like there was before so it must have been how SGP was doing the auto-focus (that setting you mentioned, Alan). The stars arn't perfect but it's an improvement. I think there is very minor tilt. I don't think seeing conditions were the best as well. I am going to take some subs with the changes in SGP. Got some light cloud cover which just rolled in. _Ha_8.50_60.00_1x1_0000.fits _OIII_8.50_60.00_1x1_0000.fits

Alan, Thanks for the feedback. I will give that setting a crack. Just managed to get out tonight to do a few more tests. I actually setup NINA as I hear it has a much better auto-focus routine than SGP just to try out. Alan/Olly, thanks for the link to the tilt jig. THat looks like it will come in handy esepcially for testing indoors during the day! Luckily im a decent handy man haha.

Hey mate. I just got the last batch of the auto-focus routine (doesn't say which filter they are for but this was the focus I was getting all night). The quality I noticed will always come back between 93% - 100%. I ended up removing the tilt adapter as it was near impossile to adjust as you need to remove everything to make an adjustment and re-test. What I tried doing was removing the filter wheel, adding a 20mm spacer (acting as a dummy filter wheel) and the tilt adapter so I had access to the screws. After a few tweaks the tilt wasn't that bad so I put the filter wheel back on as it was, did another sub and there was massive tilt in one corner so that didn't work. HFD with ASTAP, I will defs look into that. If it's another clear night tonight I wll do another test but I am at breaking point now lol.

So after a few hours I did a few configurations. 56mm, 55mm and 55mm all of those with the tilt. I tried SO many settings and could not get it. Decided to do one more, back to the original 56mm. Still no good so for the sake of it I went 57mm and got this. 57mm_2.fitOfficially have given up on this. The ZWO tilt is such a crap design as it doesn't allow you to change it on the fly. Is it still tilt? Is there sag? Are my narrowband filters just crap? Is the camera sensor tilted? Is it seeing conditions and weather? This is what turned me off the hobby for a few months last year when I spent a month trying to get this right! Just attached a third 57mm I did. ASTAP shows less tilt than before. I did a re-focus. 57mm3.fit

S2 S2_120s.fit

O3 O3_120s.fit

Ha_120s.fitLooks to be the same results as last night. Tilt but from top to bottom (as the camera is in a different position).

Obtaining results now, will upload within half hour.

That is a fantastic analysis, Alan. Part of me was thinking how could it be tilt if my images ic2944 images were a lot better. Yep using auto focus with the ZWO EAF using SGP. I didn't even think that the way the software does the auto-focus as well. I will have to look into that a bit more to see what settings there are. Tonight is looking good so I will change over the adapters back to 56mm now and get ready and report back with my findings in a few hours. Hopefully the seeing is decent. Just to keep track, current spacing: - Camera: 6.5 - EFW: 20 - Spacer: 5 - Spacer: 7 - Spacer: 1 - M42-M48: 16.5 Total 56mm. Field Flat set to 7.1mm as per spec (or very close to it as it's difficult to get exact to 0.1 as the measurement increments is per 1mm). Total back focus is 63.1mm

Thanks Alan. Had the same results in ASTAP. What I can't work out is when I captured the Running Chicken my subs didn't seem as bad. Have attached a few subs over a few nights when I captured that target. Same setup and same 120 secs (I think from memory my spacing was 56mm but my flat may have been off by a bit). The tilt appears to vary a bit across different filters. but not as bad as now. I also checked the placement of the filters in the wheel and they looked good. So if it is camera tilt which is what the tests confirm, wouldn't I be getting the same tilt across all filters regardless of back focus spacing? Stupid question, could seeling conditions contribute to the variations between filters? ic 2944_Ha_120sec_1x1_Ha_0004.fit ic 2944_OIII_120sec_1x1_OIII_0008.fit ic 2944_OIII_120sec_1x1_OIII_0012.fit ic 2944_Ha_120sec_1x1_Ha_0006.fit

Hey mate. I saw that fancy tilter but yeah a little expensive. Ah, just uploaded them now. They took a while. I did one sub as normal and the second one with the camera rotated 180 degrees. Tilt remained the same so that's telling me there's tilt in the camera itself. I came across these shims which are a great idea. https://astrodymium.com/products/rotating-tilt-adjusters I got an awesome image of the Running Chicken Nebula that you can see on my AstroBin with my setup but I removed the stars so it wasn't a big deal (and it didn't seem as bad the tilt). Currently imaging NGC 6188 and want to keep the stars in so hoping to get this issue sorted. ha_55mm.fit ha_55mm_180degrees.fit

Took a few subs the other night and upon inspection of my images I saw some focus/tilt issue. Been ironing them out tonight and now looks like theres tilt. I have the ZWO tilt adapter but it's a nightmare to use. To make adjustments you need to disconnect from the PC, unplug, adjust the tilt, put back on, connect all back up, refocus and take a sub! Is there a quicker way to deal with tilt? Can confirm it is? Have attached links to the subs and a screenshot. 120s Ha, equipment (main rig) in my sig. Currently using 55mm back focus.