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NGC6888 in Cygnus. Shot this evening before cloud called a stop to proceedings. Subs: 9x 180seconds + 4x300seconds RASA + plus IDAS NB-1 filter iOptron CEM60 guided with 9x50mm finder/guider. Capture: SG Pro Processing: To Integration - APP, then PI for colour and resizing. Francis

I've knocked-up a new filter tray from a block of Delrin. Photos show (I hope) the differences between the original and the Delrin tray. Straight off the machine so needs some cleaning up. I still have to cut the 48mm thread for the filters and fit a suitable ejector pin and pull handle. As yet I have no collimation problem straight out of the box. Because the RASA's corrector lens assembly is fixed it doesn't (hasn't) needed collimation. Hyperstar is a different matter as from what I've read is an absolute pain to collimate when it's added and when removed to use the original secondary. I have an Astrozap metal dew shield for my Edge HD 8 which fits the RASA 8, this has it's own dust cap...

Caution: Celstron RASA 8 and Baader UFC filter changer problems. I’ve just purchased a Celestron RASA 8 from First Light Optics (FLO) which is great, no problems with the RASA 8. My problems came when I wanted to fit a filter changer to the RASA 8 to take advantage of the new (ish) multi narrow band filters available for OSC cameras, specifically in my case an ASI 294MC Pro. I bought a Baader Universal Filter Changer (UFC) from a fellow StarGazersLounge (SGL) member. The UFC was in pristine condition and from looking at Baader’s specification sheet showing all the adapter plates for the UFC’s base (#24591110) I could initially see no problem in finding the right front and back plates to suit. Wrong. The problem for RASA 8 users is the shorter back focal distance 25mm from the front of the RASA 8, T threaded mounting plate (29mm from the front of the central lens assembly mounting). For me to achieve this spacing I had to mount the UFC backwards onto the RASA’s T threaded mounting plate (Baader part number #2459126) would have been fine and kept the UFC facing the right way IF there had been a female mounting plate for the ASI 294MC Pro for the other side. The UFC came with a #2459130 female mounting plate in to which the 294MC fitted. I now had to fit the UFC to the RASA. I’ve ended up machining a new mounting plate for the UFC as there are no female T threaded plates. This has allowed me to attain the 25mm spacing required but it’s left me with having to insert filters with the wrong face to the sky (RASA side). I emailed Baader (AKA-David Hinds) to ask if there were other mounting plates or a modified filter drawer so filters could be inserted correctly – no, was the basic reply. So I had to think about how to get round the problem or reversed filters. Solution (for me) has been to make a modified filter drawer so filters can be inserted the correct way round. Currently in a mock-up state (which fits the UFC base unit) I’m awaiting materials to make the final thing. The photos show the original Baader UFC with the wood mock-up. Differences should be evident but what I’ve basically done is to move the filter mounting plate from one side of the filter drawer to the other. Final photo shows the plate I've made to attach the UFC to the RASA male T threaded mounting. F Milsom 2nd November 2019.

An explosive looking flame sending hot lava down past a spectator.... IC434 10x 120s, RASA8 f2, IDAS NB-1

Portrayed horizontal for those who like it laying down. Details: Camera: ASI 294MC Pro cooled to -20°C, gain 122, offset 30. Subs: Four panels each 4x 120s. Processing: APP (cosmetic correction and stacking) panels saved as tiff. Photoshop manual joining of the panels and tidying the joins, PI for colour work, back to PS to tidy up and save to jpg for display. Mount iOptron CEM60 Standard on Tri-pier Scope Celestron RASA 8 with IDAS NB-1 filter.

My own fault (I was the only one there so can't blame anyone else 🤫). I woke about 3 am this morning and looked out on stars 😀, so down stair open the obs, grab a coffee, down to business... I did a quick frame/mosaic sequence in SG Pro covering the area between the flame and M42 - 4 panels. I set-up to do 4 x 120s subs per panel to see what I'd get. Trouble was I miss judged the rotation on the top panel with the flame neb - set the sequence going only to come back 20 mins later to see that they were rotated by a long way. Let the sequence finish the 4 panels, closed down and back to bed... Because of the rotated frames I've had to heavily crop the image each side. Must try harder (heard that somewhere before!)

Might just want to ease off on the background a touch - I think you're loosing fine detail because of it.

Details: Mount iOptron CEM60 Standard Scope Celestron RASA 8 with 9x 50mm guide scope Cameras: ASI 294MC Pro OSC main camera, ASI 120MM Guider camera Processing: Initial process to integration APP, Colour work: PI further work in PS converting Red channel to new luminance channel and combining - levels to suit.

Hi Roland - If you'd read the earlier post you'd have seen that the 'teckie' stuff comes later. I've had the rasa a couple of days, there are issues and they will be looked at in due course.

Hi Dave - Camera is the ASI 294MC Pro, the filter is an IDAS NB-1 dual narrow band. I've had to mount the filter the wrong way round at present - I need an adapter to reverse it so it faces to sky with it's front face. Getting there. It also seems to be missing some H-alpha probably for the same reason.

Second light night images These are imaged and process in the same way as those above. Just enjoying getting images at the moment - work on the teckie sides latter when I get more familiar with the scope/camera/filter combos.

Holds focus well. Though temps have been quite stable over the short sessions I've had over the last few days- time will tell

Thanks Mark - You should see me at some stage next week end. Really want to meet some of the SGLer's and FLOer's in person

Thanks Grant, Still a few bits to sort out. The quoted 25mm spacing definitely requires a filter of some sort in place. I seem to have knocked the mount at some stage the stars at the edges/corners look like a PA adjustment is needed. I think this scope could become addictive...

First light session with a Celestron RASA 8, Baader NB-1 filter, ASI294MC Pro. Guided with PHD2 on an iOptron CEM60 standard mount. Subs: 8 x 120s Processing via APP (to integration) then PI for colour work

Few more from first light session. Process change: Initial process for these were APP to integration then PI for colour work. Horse head (IC434) 5x 120s M42 10x30s 10x60s 6x120s Rosette ngc4422 5x120s

Woke (too) early this morning to find it clear 🙂 as the RASA was still set-up from last evenings efforts I decided to try a few targets. IC405 is the only one processed at the moment. The image comprises 10x 120s subs, gain 122 offset 30 on the ASI294 MC Pro. I can see that at some stage I've upset the PA but still like the image. CEM60 Standard mount, processed in PI no calibration frames. Process after integration: ABE, Background neutralisation, colour calibration, saturation and histogram transformation - saved as 16 bit tiff and 8 bit jpg. More to follow if I can stay awake...

Well an improvement but I think I still have a spacing issue.... Shot through cloud (it was there when I set-up) just disappeared as soon as I started the sequence run. Captured the smiley face anyway 🙂 1 minute sub on ngc6995. RASA 8 ASI 2994 MC Pro. Processed in PI.

Be my first SGL SP so looking forward to seeing some of the mug shots for real! (you may not feel the same)...

Frightening when your new scope throws a wobbly on it's first outing. Thankfully the causes have been found (hopefully). First was cables from the camera didn't have enough slack and when I pushed the dew shield on it tightened them further pulling the camera to one side. Next which only aided the former was that the Baader filter draw wasn't fully tightened against the RASA T thread so there was a little play. It felt tight enough when I set up, but only after having to shut down pronto because there was wet stuff falling I found it turned about an eighth of a turn further... So you can see on the images that the focus is a vertical area approximately central with focus falling off each side due to camera tilt. I found that the threads between the filter drawer and the RASA T thread mounting plate were binding which is why I thought they were tight. A little touch of candle wax on the thread has stopped the binding and the two parts fit together easily. The images: The white light was 5 x 120s subs - Gain 120 offset 30. The NB image (using an IDAS NB-1 filter) was 5 x 180s. Sadly rain cut short this first light. Interestingly though these were processed in PI but I had no calibration subs so these are light frames only and the dreaded amp-glow isn't there. ABE cured the illumination across the frame. Must try this again with more subs...

Probably NOT dithering you've strengthened the R/B pixels. Always good to dither as you break-up/even out the background noise.

I purchased an 8 inch f2.0 RASA (Rowe-Ackermann Schmidt Astrograph) from FLO. It arrived via DPD this afternoon along with an IDAS NB-1 filter. The OTA was double boxed in heavy weight cardboard with ridged foam inserts to provide support and cushioning. All OK removing the scope from the box. I have a Celestron motor focuser from another scope so I spent some time fitting that and calibrating. No problems (yet), I decided to tinker around in doors rather than in the observatory as I have more room in the kitchen. I connected everything up via a Pegasus Pocket power box to the lappy. Downloaded the latest drivers for the motor focuser from Celestron. I run SG Pro as my pointing/tracking/capture software, it recognised the focus motor, the Pegasus power box, the asi120mm (on the 9 x50 guide scope) and the ASI 294MC Pro on the RASA. Great stuff. Then I hit a snag. I needed to take the glass filter out of the RASA as I intend to use filters with this OTA and Celestron don't recommend using multiple glass filters due to focus shift and the sweet plane is quite critical with the 8 inch RASA. There are 2 little notches either side of the glass window but it was screwed in too tight to remove unaided - I ended up getting a short engineers rule, engaging that in the notches and un screwing it that way. I'm using a Baader universal filter drawer with a 2" insert allowing me to swap filters as needed although at present it will be either a UV/IR cut filter for straight OSC recording or the IDAS NB-1 to capture Ha and OIII/Hb. So I positioned it on a worktop and pointed it outside at a distant tree. All connected through SGPro and the focuser refused to work. Ran on the Celestron calibration software but refused to run through SGPro. After a great deal of faffing about I found the problem: Both the Pegasus Pocket Power box and the focuser were trying to communicate through the same comm port. Why is it I never go for the simple stuff first.... Anyway with that sorted it was easy to focus on the tree then align the finder/guider scope up with the RASA. Once I get round to seeing some stars I'll do a first light review TBC

👍 Mine arrived today along with the clouds...

I'm seriously thinking about getting one of these filters to go with my ASI294MC Pro. I'm trying to find an unbiased review of the filter. Retailers seem to put forward the blurb from the IDAS site. There are clearly sponsored videos on Y-T. So I'm looking for some unbiased user feedback please. It states it's designed to use with optics up to a 14° incidence angle so my future 8 inch RASA just scrapes inside that limit. If anyone has used it with a fast optic your thought would be very helpful. Cheers

Great image Tony, This with the 294 and the Tri-band or Quad-band as they have different red pass band widths? Might be worth imaging without the narrow band combination filters for star colour (+UV/IR Cut) then over lay the starless NB image - just a thought.