Icesheet

Thanks for the informative, detailed reply. I guess my main interests at this focal length are nebulae, both in broadband and with a dual narrowband filter, and the dark dusty nebulae that have become more popular recently. As I write that, it’s obvious I should prioritise signal over everything else. Especially, since I’m rarely collecting more than 4-6 hours on one target. Also, I notice I’m pushing my images too far when processing. The remedy to that is likely more integration time or something that collects signal faster. Interesting comments on the Tak star shapes. I was aware of the reverse lighthouse effect and it’s not something that bothers me in terms of an aberration or artefact (halos are my pet peeve). Hadn’t heard about cats eye bokeh though. Had a look online and see its inherent of the Petzval design. Is that what the new flattener was/is trying to correct? I’m curious to hear of the other refractors that operate at f4.8 that you think are better than the FSQ-85. And those designed like the AP 110? (I’m in that lottery!). I’ve learned that I’ll likely be a OSC man with dual narrowband filters. Tried the mono route and had so many unfinished images. I’ve also learned that weight and complexity of set up hinder me. Had an EQ6R and could never be bothered to take it out. Now have a Rainbow RST and with the Askar FRA400 I’ve never been so productive, albeit I feel I’m lacking something in my images. The comments here are largely pro RASA, or fast reflector of sorts. I think my main worry is that if the set up ends up being a nuisance I’ll give up. However, won’t know until I try. I think I’ll probably just sit on this until later in the year as come April the night will already be short. That gives me a chance to keep an eye on the market for a deal.

You certainty are prolific with it and produce cracking images! It’s not so much primarily imaging for stars. It’s the work involved getting them good enough and if the process would defeat me before I get to that point. I would love to see 6hrs on a range of targets from both scopes with comparable conditions to see what the difference in a final image would be. Maybe I should buy both and test 😂

Not off topic at all! Where are they available? I’m on a waiting list at Kyoei in Japan, where the Tak gear is available quite a bit cheaper than Europe. Since I have to deal with customs wherever I order from it makes sense for me to order from there.

I agree the FRA300 looks great but then I’m surprised you think the FSQ has poor performance with the new flattener. Looks better corrected and smaller spots than FRA300 although can’t find any quoted RMS radius. The new reducer for the Tak does quote spot size though and it’s 1.6micron on axis, 1.9 at APSC and 3.9micron at full frame. Of course price difference aside.

I wasn’t making an argument, I was asking a question. I was curious to know, based on my local conditions what would resolve more detail and provide a sharper image. I certainly do not, and your images as well as your apparent change in stance regarding such scopes is part of the reason they interest me. However, I see the other side too. I am interested in spot diagrams and star shapes. I’m looking for the right balance of going deeper in my limited imaging time but getting the most from the optics in terms of sharpness and star shapes. It’s also about me choosing something that fits my habits. The sampling rates and FL of both are fairly similar so maybe there is a quasi-objective answer of what would provide the more pleasing image. Anyway all good input, don’t know if it’s made a decision any easier for me though 😆

Very nearly bought the FRA300 when I ended up with the FRA400. Probably should have tbh as it seems to have tighter stars than the 400. Still, I think I would prefer 400-500 now as I’ll use the Samyang 135 and have a Tak TSA120 at nearly 900mm FL. Seems like a nice set up, I’ve seen some of your images 👍

Yeah it seems like the RASA will give you back what you’re willing to put in and that may be where I fall down. I would absolutely set out with the right intentions but I know if it starts needing more fiddling than the initial set up I will give up. I’m definitely open to more suggestions if you have any. For instance the aforementioned Epsilons are interesting but may present similar problems as the RASA. The new WO Pleiades look interesting but I’m not sure I’m ready to be an early adopter. Maybe a used FSQ106 could be an option? In terms of size and weight it has to go on an RST135 so RASA8 size and weight is probably max. It doesn’t have to be the fastest but I see on average that I collect 4-6hrs data per night (from Bortle 4) and as I rarely get consecutive clear nights that’s usually all I’ll collect on one target. So, it doesn’t necessarily need to be F2 but the faster the better.

I have one. That will be my super wide field and travel rig.

I’m actually on a waiting list for the Epsilon 160ED but have been told it will likely be years before it materialises. The 130D seems as scarce these days. I’m not sure it would be any easier getting dialling in an Epsilon over the RASA. Although image circle and field correction should be better. Not quite as fast though. Are you saying the flat field on the FSQ is not good even with the new flattener? When I look at the spots and some examples I’ve seen on forums it seems pretty much as good as it gets at this FL with a refractor and the IMX571. The new reducer looks fantastic too. That being said, you are paying a premium and not guaranteed the performance. The Vixen VSD90 looks like it may have the best correction and performance but it’s more than I want to spend. I’m not ruling out ever going back to mono but I plan to stick with OSC at the moment so the filter issue doesn’t affect me.

Thanks for the opinion. Seems like yours is like most. If you can work with the quirks and deficiencies of the RASA it seems most are happy. I’m maybe just a bit too apprehensive of leaving my refractor comfort zone.

Thanks for the reply. think I maybe came across your case when I was looking into the FSQ-85. A nightmare scenario for you and one I would hope to avoid. It does seem it may have been a collimation issue though? I’d hope if I bought new I would be able to return rather wait for a lengthy repair. I’m aware I could end up in a similar scenario though, but as @Elp mentioned, the RASA’s have had their fair share of issues as well. I guess any scope is a little bit of a lottery, even the supposed premium offerings. I do agree it’s frustrating that they had to add a flattener to correct issues exposed by small pixel cameras. It negates the benefit of the native design.

Thanks. It does seem a common theme that people don’t look back when they go F2. Also, from comments I’ve seen it seems issues are more related to tilt and back focus rather than collimation. If these are one time problems I’m willing to work with it as likely is have similar hurdles setting up a refractor initially, although maybe not as challenging. Yeah, my plan if I both would be to get new batch and somewhere that accepts returns if I realise it’s not for me. I have no issues with Askar scopes. I have two and they do what they are supposed to but to achieve the round stars they sacrifice sharpness and I’ve found that it’s bothering me a bit. Maybe I’m asking too much though.

I don't have enough clear nights to justify the amount of scopes I have so I’m going to thin down, again! I currently have a number in the 250-400mm FL range and I plan to sell them and replace with one dedicated imaging scope to mate with an ASI2600MC Currently, the main contenders are: Tak FSQ-85 (1.72”/px) 450mm FL, option of 330mm at f3.9 Pro’s • Proven performer to APS-C (assuming good sample), even better correction with new flattener • Ease of use • New reducer looks fantastic at f3.9 and relatively reasonably priced Con’s • Frustrating having to deal with back focus on what’s supposed to be flat field Petzval • Risk of sample variation, expensive if collimation out • Focuser not good enough? RASA8 (1.94”/ px) 400mm FL Pro’s • Blazing speed • Resolve more detail with >aperture? • Cheaper Con’s • Collimation • Not easy to get good correction at edge of APSC? • Limited to ASPC and will need new filters. According to MeteoBlue my local seeing is tends to be in the 1.5-2 arc sec range and I’m in Bortle 4 according to light pollution maps. Have no idea if this is the case but in either case the sampling of both scopes seems ok. More important to me is to make use of the limited clear skies I have. I tend to not image one target over multiple nights so I want to collect as much as possible in one night! That of course favours the RASA but I need to balance that with ease of use. If there’s regular fiddling to be done I tend to give up and losing a night to issues is more of an issue than what’s gained from the extra photons on the sensor. I’ve become quite picky with star shapes and sharpness. I’ve been using a FRA400 recently which is easy to use and gives me round stars but images appear a bit soft for me. I’m curious to hear what people might think would produce the sharper cleaner image out of the RASA/ Tak? Baby Q seems tighter with spot size etc but is this offset by the extra aperture of the RASA? I realise a lot of the processing tools we have these days can negate much of the negatives of both setups but I would like the easiest data to work with to start with. Right now I’m leaning to the Tak but I would say that’s mainly because of my trepidation of dealing with collimation etc. Otherwise, I feel it’s a toss up. Will cross post this on another site so apologies if you read this twice and thanks for reading and even better if you offer an opinion! Chris

I had clear skies on a new moon so decided to attempt another dark nebula. Managed to collect 5hrs data on the Shark Nebula with an Askar FRA400 and ASI2600MC. Always tough finding that balance of bringing out the dust and not pushing things too far. Hopefully, I have!

Yeah it’s a bit daunting when you first start using the software but worth it! There are a few ways, but here I just used Curves Transformation and globally pulled up the saturation.

Is this your first ever image? Even if not it's fantastic. Great shot and more data will only make it better. What did you use for processing? One thing you might want to look at is the galaxy is a little blown out. I guess you were trying to show the fainter extents of M51? However, in doing so I think you are losing a lot of the detail and colour you have there. I hope you don't mind but I took your image and lowered the highlights in LightRoom, then increased the saturation in Pixinsight and gave it a blast of BlurXterminator. A lot if this is subjective so forgive me if it's not to your taste but I think you can see more detail here and little bit more of the colour. I think this video from Adam Block is great if you have PixInsight. Otherwise there are other ways. In any case, great image. Thanks for sharing and please post more!

Yes, I used SCNR at some point in the process. I’ll need to remember that in the future Thanks! ☺️

Fed up of snow ❄️, rain ☔️, cloud ☁️ here so had a bash at the excellent IKO M81 and M82 data set from @FLO. Not done much Ha LRGB processing so this was a good test for me. Fairly happy with it although for some reason the filaments on Cigar Galaxy came out purple/ pink. No idea how I managed that. Grateful that we have free resources like this! Also, added a widefield shot of the galaxies with Coddington’s nebula that I took with my little Tak FS60 last year. Amazing how much the focal length alters the perception and context of objects!

I would love it if my destruction ended up like this! Great image 👏🏻

I didn't specifically move because it was mirrorless, just that a modded EOS R came on the market. Before that I had a modded 6D and that is generally a well thought of DSLR for astrophotography. If you say it's mainly DSO stuff you're interested in then I would encourage you to get a dedicated cooled astrocamera instead. I've only used a modded 6D and EOS R, which I've been happy with. Really couldn't say if they are any better or worse than others. @geeklee covered it regarding scopes not covering full frame. It's just something to bear in mind so you don't shell out on a very expensive full frame sensor only to find out you can't make use of it.

It is a stock camera but the use of an additional Ha filter is not redundant. In fact in some scenarios it will be highly recommended. Although the Ra is more sensitive to the Ha spectrum than a normal EOS R it still benefits from a filter with a narrow band pass to really bring out those Ha emissions. It sounds like you are more tended towards DSO photography and in that case for the price of an EOS Ra you could have a very good dedicated astro camera and a decent stock mirrorless for daytime photography. For me an Ra or modded camera really come into their own when you are primarily shooting astro landscapes and might only shoot DSO stuff now and again. Bear in mind many telescopes don’t support full frame. There is no doubt that an EOS Ra can be your only astro camera. Check out a guy called Mark Shelley but if you want it do it all it’s not worth the compromise in my opinion. I have a modded EOS R btw. Use it exclusively for astro landscapes.

Does he say he is sponsored? I have heard him say Askar sent scopes to review but sponsored is a completely different thing. That would definitely compromise objectivity when reviewing. Having said that I’ve always felt he’s impartial when I’ve watched any of his reviews.

No problem 😊 I would add one more thing. If you haven’t budgeted for a guide scope/ cam and some processing software I would set aside something for that.

With that mount, camera and budget there are numerous options open to you! Instead of suggesting a random scope my question is do you know what sort of targets you would like to image the most? E.g Galaxies, Nebulae.. etc. Theres not really a one scope fits all when it comes to DSO. You can use these sites to see how various targets you might want to image frame at various focal lengths with the ASI2600MC. https://telescopius.com or https://astronomy.tools Since you are new, the most likely recommendation will be a small to medium refractor in the 300-600mm FL range. It’s generally considered the most forgiving and fun entry to astrophotography. A petzval design may be beneficial too as it means you do not need to mess with backspacing to get focus and good stars across the frame. Then with some experience you can move to a scope with a longer FL if you want to go after smaller targets. I say narrow down the focal length that frames the targets you are most interested in best then start looking at options. Edit to add: Anotjer good place is to look at pictures taken with the ASI2600 (or similar) on Astrobin then see what scope they are using. It will give you a general idea as well Good luck!

Yeah, I actually found out I was using a wide gamut profile and have now changed it to the standard profile. Doesn’t seem to have changed anything immediately but l’m going to check more tomorrow. Will Google it and check out those links, thanks 👍