Clarkey

I think you need to check your priorities 🤣

Look on the bright side - you can save the money by turning off your heating while you are outside imaging in the winter. Every cloud....😁

Mine stopped talking to me years ago.🤣 Definitely. Excellent scope for the money.

I got my SM 90mm just before new year (and the price increase). Although at this point I was largely using my longer FL scopes for galaxy imaging, I did use the SM a few times. In most areas I think it is excellent. It is well made with a focuser that works for AP - most of my other scopes have not been so good. The made-to-measure flattener reducer is also excellent. Optically it is also very good with no visible CA. My only question with it is the cooling. I set it up along side my ED80 on my dual rig (first and only use so far) and the SM focus drifted way more than the ED80 which stayed pretty constant. As I put my scopes out in plenty of time, the only reason I can see for this is cooling of the optics being very slow. I will be trying it again soon with the new season starting so I can see if will always be a potential problem. If you are using it on its own with an auto-focuser I would not hesitate to get one (especially if you can get one of the ex-demo models cheap). These images are using the SM90. The top one is LRGB plus Ha - something like 8 hours total integration using the F4.8 flattener. The second was a combination of ED80 with a Canon 600D plus Luminance with the SM90. The final image was the SM90 only at F6 using the SM flattener. I did not use any star reduction on these images so you can make your own decision on how 'good' the stars are. To be honest the processing was fairly minimal -as was the set up. On the last image the flattener probably needed to be moved out a fraction, but on the California nebula it was plug and play.

Rising Cam IMX571. Pretty much the same camera but half the price. Slight gamble with warranty but much better value. There other manufacturers selling it under a different name at low prices too.

Back today!!! Yey!!!!😄😄😄

As far as I know there is not much between them optically. Focusers and other bits might be slightly different, but as far as I'm aware pretty much the same. My only question is regarding cool down time with carbon tubes. My 90mm Stella refractor is very slow to cool.

On your own there. I still have the ZWO filters. Astronomik and Antila seem to get good reviews. Depends on how deep your pockets are....

I would agree with @scotty38 that the 7 slots is a definite benefit (even more so if using unmounted filters). You don't want to be opening up your filter wheel to keep changing filters. If you only do RGB or narrowband you would be OK. As for filter sizes, I think for the 533, 1.25 are fine. For the APS-C you would probably get away with 31mm filters - but it will depend a bit on the scope and set up. I would check on the Astronomy tools website which has a filter size calculator. If you are using 'cheaper' filters then it might be worth going larger as the cost difference is small. I think you are probably better off spending the extra on better filters rather than larger.

I think maybe you are over-thinking this! The 'back-focus' is just the focus point as with any other scope. For normal AP I use the four extensions provided (100mm) and then the focuser and focus normally - but the focus point is a long way back. As the primary and secondary mirrors are not moving you are not changing anything in terms of the optics. Although the supplier focuser is OK, I did change mine to a Baader ST just to make sure everything was rock solid. Not sure it was necessary really but it was nice, new and shiny😁. I don't have my rig set up at the moment, but here is a picture of roughly where my RC8 focuses (there is a tilt adjuster too which adds about 20mm). As @Len1257 says the weight is far back. I use a combination of guidescope and homemade power box to balance.

The is also a Stella Mira flattener that might be suitable. It's design for f5 to f7 which suggests it should be ok.

Hey it's a start. It is focus and the stars are pretty round. Good start I would say. 800 iso is probably about right for the Canon. I would forget the darks and run some bias frames and flats plus increase the integration time. In terms of framing, have a look on Stellarium or similar for some interesting areas of sky.

Perhaps if your tone was a little less patronizing and condescending you would get a better response? In terms of what you are saying, whether you are right or wrong is irrelevant, you can not accuse everyone with a different view to yourself as being ignorant savages. This forum openly encourages friendly discussion and debate. If someone has a completely different view to everyone else that is accepted - not condemned or ridiculed.

How about a sky-tee with a ST120 for wide field and pick up one of the many 2nd hand 200p's for a couple of hundred pounds. Should be about on budget.

From the back of the scope to the back of the camera - making allowances for cables and approximate point of focus - is about 43cm. Bearing in mind the back heavy nature of the scope and the width, I have never had a problem with it hitting the tripod. This is with an AZ-EQ6.

You can't use the dovetail itself as it is too close to the tube you could probably attach risers or add a handle. I actually use mine to guide with an ST80 mounted on top towards the front. Helps with the balance a bit too as the RC8's are very back-heavy once loaded with photo gear. WRT the collimation - once set it needs very little, if any adjustment. Mine was pretty good from delivery and only really required a minor 'tweak' to give a slight improvement. In fact the images in my earlier post were taken before I collimated the scope. I wanted to wait until the end of Galaxy Season to start messing with it - just in case!

As I said in my post above - I don't disagree at all, I was just giving options. I would still question the FPL-51 vs FPL-53 mainly down to the manufacturing tolerances at this price point - not specifically down to design but down to individual scopes. I have an ED80 which is FPL-53 and this gives a fair bit of blue bloat and generally this is deemed 'good' optically for the money. Mine was also optically checked by FLO.

I don't disagree with any of the comments - I was just looking at options, but to a price. Given the OP original budget and FL requirement it would still be an option in my opinion. With a flattener reducer it would also give quite a fast system for AP. Personally I would go with the RC6 with a suitable flattener/reducer and bin the camera. This would remove the false colour and give a fast system at a good sampling rate. Good value too.

There will undoubtedly be some CA at F6, but nothing that could not be removed relatively easily in processing or with an L3 filter. However, looking at the specifications again the Starfield is probably a better bet. I do think there is a bit of an obsession with FPl-53 over FPL-51. A well made FPL-51 is likely to perform as well as 53

I have not used one, but I am guessing your EQ2 with a RA motor drive would be usable as a star tracker. You can use this to mount you camera as a starting point. Next stop I would suggest would be fleabay. There are expensive ED lenses which are ideal for AP, but to start with a standard widefield lens or two would get you started without having to empty your bank account. I just got a 100mm F2.8 prime lens for £30. This plus an intervalometer for the camera will get you started as a very simple set up. Yes, it will not give perfect images but you will be surprised what you can achieve. It will also allow you to try stacking and image processing before entering the financial black hole of AP. Trust me, it is addictive and expensive😁

The other thing to consider is the mount. For the longer FL you will need good tracking. What about the SM 110mm F6 doublet? Slightly more money but probably better suited to AP and a good price.

I think they are generally quite well collimated out of the box. I think many have been made worse by 'tinkering'. My method for collimation is to remove everything xcept the focuser and get the secondary perfectly aligned. I use a TSKOLLI or Reego, but you can use a simple Cheshire for that part. Once the secondary is right I use the DSI method for the primary using a star test. https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.deepskyinstruments.com/truerc/docs/DSI_Collimation_Procedure_Ver_1.0.pdf&ved=2ahUKEwi62bCmhJX5AhVMPcAKHcvBBws4ChAWegQIKBAB&usg=AOvVaw1TQ8YAhohC9_gr_IRXBo3x This works for mine but my focuser and primary mirror appear well aligned as I get no tilt issues. If this is not the case it is more tricky - but the DSI method should still work. My main advice would be adjust it SLOWLY and try to remember what you have done to put it back again. There is not a lot to say about the scope itself. I do have a home-made secondary dew heater, but I have never had a problem with the primary and dew. Cool down is pretty rapid too as it is an open tube. I have only used it with a ASI1600 which gave a good flat field. With a larger sensor you might need a flattener. I still need to try it with my IMX571 camera to determine if it is OK with and APS-C size sensor. I did change the focuser to a Baader ST. The original was OK in terms of tilt, but it did slip slightly with the autofocuser. I hope this helps. Here are a couple of images with the scope. Just remember I am far from an imaging expert!

Still a couple of weeks to go☹️

As an RC8 owner, I must say I am a fan. In terms of value for money I think they are excellent. As I am sure you have read, collimation can be a bit tricky initially - but once set it does not need much adjustment. I typically bin 2, but in all honesty, with my seeing bin 3 is probably more realistic. Also, although F8 it never 'feels' slow except when compared to my F4 scope.

I have used Cheap Astrophotography as have many others on the forums. Juan provides a good service and sells ready modified cameras.