gorann

From what I have read the chip distance should be 29 mm with the window in, and still 29 mm with a filter but then the window should be removed. I assume there are two reasons for this. First, the effect of the filter on the light path (prolonging it with 1/3 of the filter glass thickness) is removed by taking out the window. Secondly, having both a widow and a filter may cause some refelction/halo problems, but the latter is just a guess. I actually have now idea why they put the optical window in there except that it gives Celestron a reason to sell their light pollution filter that can be bought to replace the window.

Thank you both! I am aiming at something less questionable tonight😎

Thanks Adam! Stop blushing, I don't think it is Eve you are looking at😉

For reasons unknown to me I have had a few clear nights now with the moon up and about, so I am shooting Ha with the RASA 8 and not getting much sleep. Have done the Tulip and the Propeller nebulae (HaRGB just posted) so last night I aimed at the Lion nebula Sh2-132. Here is 54 x 5 min of exposures at gain 139 with ASI1600MMpro and a Baader fast Ha filter. Looks quite intimate.....

Thanks! I did remove the optical window since I am using a Ha filter for the ASI1600 (as suggested by both Celestron and Baader). Why should I put it back for the ASI2600 next time I go RGB - does it have any function that you know of?

Thanks Alan! Still at it - may be clear tonight so I aim to such up whatever Ha may reach northern Europe!

Thanks for you kind words Paul! Yes, at least now when nights still are short it has clearly been a game changer. Now I can get the data for an image in one night, or two nights if I add Ha. I am surprised how well it keeps focus (no refocusing during a night so far) and collimation has been spot on from the factory. Only issue is minor tilt in the cameras - the RASA is apparently very sensitive to this due to the low f-ratio. I can live with it and mostly fix the corner stars it in processing, and it is probably only an issue for me and other pixel peepers.

Thanks a lot Alistair. Yes it is now working hard and doing a good job. Finally astrodarkness up here and I had a few clear nights recently.

Thanks and good luck! Try to get both RGB and Ha, if you are not going for NB. I am still waiting for a Baader fast Oiii filter.....

This was the first nebulous area I shot with the RASA 8 back in August 16th. Then RGB was collected with the ASI2600MC (gain 100). Now, when the moon is out and I have a spell of clear nights I have started to collect Ha for the RGB images I caught earlier in August. For this one I managed to collect 44 x 5 min Ha (with ASI1600MM at gain 139, Baader fast Ha fiter) before the computer for unknown reasons lost the USB connection with the camera while I was a sleep. As usual Ha lifted the contrast and brought out more of the Ha background. Ha was added in PS to the red channel in blend mode lighten, and also a bit as lum. So totally about 7 hours of HaRGB data.

My first HaRGB with the RASA 8. RGB with ASI2600MC (87 x 2 min, gain 100, moonless on 25 August) and Ha with ASI1600MM (61 x 5 min, gain 139, full moon on 31 August). Baader fast Ha 2" filter. This is a Ha emission region in Cygnus and the Tulip is to the right, and adds to my Sharpless collection. Not sure if the other nebulosity in the image has any designation, but it is quite a lot of it around. There is also some nice dark nebulosity and three intriguing red filamental structures just to the left of the centre of the image. I wonder what they may be. The RGB image looked rater uniteresting so the Ha collected last night made a big difference.

That is something else! Good idea to either run the RASA or the refractors not to make your brain and computers to melt down. Mine would. Looks sturdy enough. Regarding focusing the RASA, this has been one of my main surprises with this f/2 scope. It is very easy and it keeps all night (I see on Chuck's Atrophotography on youtube that he found the same). I just zoom in on the smallest stars and make them as small as possible on the screen. When I put the Bathinov mask on after having focused on the computer screen, focus is always spot on, so I have now retired the Bathinov. Good luck!

I ordered it from FLO in June. I can see on the TS site that a new batch is promised by Baader for October so I hope FLO gets some of those too. TS is good in showing expected delivery dates and not just stating "Usually shipped 10-15 working days" like FLO. Sorry FLO but maybe you could also try to be more precise?

Very promising indeed. Yes, I have the fast Ha and am waiting for the fast OIII but Baader seem to be still working on the next batch. 3 minute subs - this is a fast scope! What camera did you use?

You are a brave guy! Will be very interesting to see how it goes. I think I wait with fireing up my Esprits on the Mesu until the moon leaves us.

My RASA 8 is ready for some serious Ha collection success (or failure🥴) tonight. Remeber Tomato that you need to put your camera cables in a curve to avoid ugly spikes. I did it with bent steel weire (the type I use for tieing up garden plants) and electric tape. Seems to be no need for heating the front of the scope - enough heat is produced by the cooled camera if you have a dew shield. And you may want to get an extra Losmandy bar on the top - stabilizes the tube and great for firmly attaching a guide scope. Celestron have a dedicated bar that is reasonably priced.

Inspired by the dusty version of @wimvb I brought back some dust from an earlier version in my processing run.

Here is the filter slider I will be using tonight for NB imaging. https://www.baader-planetarium.co.uk/2019/11/28/baaders-rasa-8-ufc-telescope-side-adaptor/ It cannot be used for cameras with more than 13 mm chip distance, so the ASI1600 is fine (after adding 6.5 mm) but not those with 17.5 mm distance, like ASI2600 and ASI071. For those you need the adapter I linked to in the earlier reply.

Great version Wim. You have gone for dust and I for contrast against the background sky. Maybe a 50:50 mix would nail it. And red-brown it is!

Not sure what filters will fit in the optical window. Celestron sells a dedicated one but it is just for light pollution. I assume that you could compare the hight of the optical window to that of any 2" filter you have to see if it could fit (and if it is a normal 2" filter thread). I have not removed the optical window - why is it recommended in the manual? I missed that. EDIT: I read up a bit and it seems like the optical window should be removed if you put other filters into the lightpath. Baader suggest this for their filter slider (which I have). With the ASI2600MC I did not use any filters and the the optical window can be in place. So tonight I will try Ha imaging with the ASI1600MM and a Baader high speed Ha filter (2") in the slider. I will then remove the optical window and hope I got the spacing just about right (I have a 6.5 mm female to female T2 from Agena Astro between the camera and filter slider) so the total telescope to chip distance will be 29.4 mm which adds a little extra needed when there is a filter in the path.

That was a quick delivery, especially nowadays! You must have hit a worm hole in corona space-time. Nice first light Tomato! Yes, I have also been wondering a bit about that "squidgy material" since I also have a tilt issue. I just ordered one of these so I could use filters on my ASI2600 (with a 17.5 mm chip distance I cannot use a filter slider for it so I would need to use my ASI1600MM). It hopefully lacks that "squidgy material". https://www.pierro-astro.com/materiel-astronomique/hyperstar-et-rasa/adaptateur-filtres-pour-rasa-8-compatible-zwo_detail

Talking about wide field @ollypenrice, it just struck me how bl-dy big this dark nebula is. My image was taken with the same FOV that I managed to get the whole M31 into. Those dark monsters could eat a whole galaxy in minutes:

Hmm. This is SGL, that sounds like a Cloudy Nights comment.

Most probably Olly, but when the circle is closed maybe one day you find yourself doing 14" imaging on the most distant targets your skies can reach, and there is no end to them😉

Thanks for the reassurance Olly! And then I have the 14" Meade that will never run out of targets😄