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Recently I bought a RASA-8 from a fellow club member (my second RASA 8 having sold the first - fool that I am). Whilst with my original RASA I was using an ASi533 it was possible to fit a filter drawer between the RASA's camera mounting plate and the 533 because the 533 has only a 6.5mm back focus. However now I have an ASi2600MC Duo which has a 17.5mm back focus. Searching the web I can't find a filter drawer/slider for the combination of a RASA+17.5mm BF camera. Anyone not knowing why there's a problem. The RASA-8 has a total working back focal distance of 28.73mm with the ASi533 and it's 6.5mm back focus you're left with a hefty 22.23mm to fit a filter drawer into. For cameras with a 17.5mm back focal distance you're left with just 11.23mm. Then there's the thickness of the camera mounting plate, the filter depth.... So. My aim was/is to be able to place unmodified mounted filters between the camera mounting plate and my camera without having to remove the camera each time a filter needed changing. This prototype (MK 1) will take filters with a total depth (side wall + 48mm thread) no greater than 7.8mm For me this means that my IDAS NBZ and Askar 6nm Ha/OIII filters are okay. My Baader UV/IR cut filter is too tall and if I'm going to use this filter then I will have to reduce the total depth of the side wall to 7.8mm or below. I can't see how I can get any more free space for deeper filters. What I've done: I've made a new camera mounting plate to replace the 42mm camera adapter plate supplied the the RASA originally (I still need to slot this plate to access the RASA's tilt adjusters) and cut a channel across the plate to the level of the clamp (Photo 02). The adapter could have been made to the same thickness as the clamp's retaining edge but I felt that by making it thicker and adding a rebated edge down to the thickness of the clamp's retainer it would give me a better positional register for the adapter/camera assembly. I can still rotate the adapter/camera assembly for framing if needed. The unit is in two parts: the new adapter plate and camera mounting plate. On the MK 1 prototype only two 2.5mm machine screws hold these parts together. On the final four possibly five 2.5mm machine screws will be used to register and secure the two parts together. The upper camera mounting plate has the deeper channel and the 54mm camera mounting thread. The channel depth has been taken to almost it's maximum as there is only 0.42mm of metal left between the channel and the camera front face which I flet should be left to protect the camera from the filter drawer entry/exit motions. Currently waiting on some metal to make the filter drawers themselves and some shorter 2.5mm machine screws so the don't go right through on MK-2 ! TBC...

Ian, I use a RASA 8 (this is my second I foolishly sold the first one and regretted it. Couldn’t wait to replace it). Like you I have a RASA to collect data when the skies permit. I have not experienced a problem with tilt on either of the RASA 8’s I’ve owned. The biggest single problem is the choice of camera you put on the front end. Specifically the back focus of that camera. If you chose a camera like the ASi533 with a 6.5mm back focus then you will have the option of fitting a filter drawer and use various filters with your RASA. If you chose a camera with a 17.5mm back focus you can’t fit a filter drawer and you are limited to finding a way of attaching individual filters and fitting them to the camera before you attach the camera to the RASA each time. Changing filters and realigning the camera being somewhat awkward! (I’m currently modifying my RASA 8 so I can get a filter slide with a 17.5mm back focus camera). I used an ASi533 with my first RASA and they make a great pairing. The ASi294 is also a good match but does have the amp glow problem which some seem to get round easily others not so (me)! I can’t comment on the short focus Newt’s but I have owned and still own a 10 inch f4 newt . If as you appear to have an obsy the your not going to move the scope around too much it will hold collimation quite well. If your going to do much transporting with fast optics like that then collimation/tilt may become an issue.

Through variable cloud I've put the best 12x 60s subs together of 40. Processed in PI. No attempt to register the comet, star registration only. The comet is the little blue smudge low mid frame. Captured 7:30 - 8:00 ish sky still quite light. Weather forcast now is poor until after H2 passes M106 for me sadly.

Earlier in the week last night was supposed to be clear after what seems weeks of cloud! It wasn't, thin to thickish variable cloud until 11 ish when PHD packed in with lost star syndrome. So I got a couple of short sub sets on NGC7023 and M33. M33 suffered the most from cloud thickening but neither escaped entirely. 10x 240s sets for each Hope you like.

If you're thinking of using the same guide camera for each application (not specified) then the 70mm will give you the widest FoV which would be useful in poorer areas of sky in locating a suitable guidstar, plus you can alway align a guide scope to guide on the object being photographed (i.e. a comet head) which you can't with an OAG. An OAG however will be using the same fl as the main image train which should lead to better guiding. Long fl's and OAG's need reasonable star fields to ensure enough guide stars within a FoV. My2 p'th...

Yes it can - I've got green bits 😀but not in the right places 😡

?

Trees growing well anyway!

We all see what we want to see…

He has a dark witch in front of him - but hey he's got a blue laser so no problem...

Many thanks Olly for those kind words. Early days (2 days!) with the RASA and the 2600MC Duo so getting used to what they will give me. After reading your comment I've run some tests with the star image from the NAN-Pelican image using RC-Astro Blur-XT (taking a small croped area so I'm not here all week!) and I've ended up running both the stars only images with a 0.35 setting for sharpening and leaving the halo setting at zero as the halo is reduced anyway. So I hope these are more to your liking. In for a few days of poor weather now so time to experiment further. Good to get comments from others about how images can be improved. Many thanks

Rob, if you look back through the moans on this forum it’s a wonder anyone is still practicing this hobby. People here (me too) will moan about the weather whichever way it swings. It’s a great hobby. You’ll get frustrated and elated all. In the same evening. USB cables will have rude words uttered on a regular basis but you’ll gaze at that image as the detail unfolds before you and all the woes will vanish… Until the next night… Dip in with some used kit first to get the hang of things. If you get hooked then start emptying the piggy bank.

I have been through that type of situation with kit in the past where moving either a loaded tripod or tripod plus kit in smaller units. One thing I did after many nights of setting up getting my PA etc was to mark (the patio) in my case where the tips of the tripod legs touched the ground and next morning drill 3 holes in the patio just big enought to take the tripod leg points. Mark one legs as always in X direction (mine was nearest the kitchen wall) if you can leave the mount fixed to the tripod so much the better. Any little routine like that where bits of kit can be left assembled as units so fewer operations are needed to get going will speed up both set-up and take down time.

Still playing with the RASA 8 and IDAS NBZ filter combo. I like it as there seems very little in the way of halo's from brighter stars. This is a 10x 240s combo from last night (22-09-2023). Processed in PI only. AC Astro's Star Exterminator used and the two parts of the image processed together. However the star/nebulosity image is from the initial integration. I didn't like the two part offering but did like the neulosity only image.

This year has been bad, worse than most. An observatory of some sort helps, even just a pier with the mount set-up so you don't need major PA's each session. Set-up and break-down are often the off putting stages because they're basically non productive so reducing them or removing them is a real bonus. I have a RoR obsy and my set-up is usually plugging in a power lead to a wall socket and connecting my laptop to the mount/camera (oh and rolling back the roof!).

Shot last night as a test for my newly aquired (new to me) RASA 8 and IDAS NBZ filter combo. Captured with an ASI2600MC Duo unity gain, 10x 240s subs and processed in PI only. I used RC Astro's StarExterminator to remove the starfield and processed the nebulosity separately. The stars were simply given a saturation boost before recombining. I regreted selling my RASA 8 a few years back and I couldn't resist this when a fellow club member decided to sell his.

My Duo has red leads. An older usb 3.0 lead in the Obsy will not connect to the Duo, all other cameras are okay ? Not sure if it’s to do with the extra traffic from the inbuilt guide cam.

Grand imaging Dave as always.