5 hours ago, apaulo said:

if you want fine sawdust empty it out of any wood sander bag

That’s sanding dust and probably too fine unless a really coarse graded abrasive is used.

First imaging test with the filter drawer 15x 240s filter: Baader UV/IR cut.

Parts still to be black anodised, star images are good right to the corners. This has been cropped a little for composition but pleased with things so far.

Great result. Something to build on rather than it all going wrong and first light being a disaster.

I had an MN190 many years ago. It's a good scope and your result proves it. Look forward to more results from that combination in the future.

Blackboard paint mixed with sawdust… it doesn’t have to be dead black just kill reflections

I've cleaned all the engineers 'blue' off the pieces now and taken off all the burrs so it's now waiting for the final clean-up before being anodised (black). Three more photos of it fitted back on the camera. The corners of each of the filter holders sits just inside the clamp nut's outside diameter so shouldn't cause any extra diffraction effects. There will be a small tuck-away lever to insert/remove the filter holders which will also act as a lock to stop the filters moving. I managed to get my Baader UV/IR cut filter in but only by machining 0.8mm off the leading edge of the filter's mounting (I did take the filter glass out first).

Photos are fairly self evident: My filters in their holders, Interior view with the UV/IR cut filter and a view into the filter slot with a filter in place.

(the inserted filter in the bottom photo is the wrong way up!!!)

Thanks for looking

For me an AA 26C just couldn’t get colour to look right or debayer cleanly.

I ended up making a support jig for the different stages of producing the filter trays/sliders.

The first photo shows the three stages: left most is the sizing of the blanks. Here I position rough sawn blanks each held in place with three 5mm cap head screws. Blanks are over size by about 0.5 - 0.75mm all round. Mid position is where the main maching takes place the central hole is cut, the 180° outside curve and the rebate the filter screws down onto. The righthand area is where the 48mm filter thread is cut.

Photo 2 shows a blank being sized to 50.75 x 65 mm with a 2mm radius on each corner. (The tape over the other areas is to keep the swarf out until they're needed.

Photo 3 shows 5 filter trays/sliders ready for the threads to be cut. That should give me 6 trays/holders.

Thread cutting tomorrow and a small mod to the mid section of the camera adapter. Big clean up and blackening all the parts.

TBC...

Photo 1

Photo 2

Photo 3

3 hours ago, globular said:- but if you're modifying an existing rasa connecting plate to make this then you won't have a surplus of them to make more. No worries.

Keep posting updates - can't wait to see the finished working version.
 

I’m making new rasa camera connecting plates because they need a channel cut across them to accept the filter slider. Plus I’ve modified how the clamping nut registers against the camera mounting plate.

26 minutes ago, gorann said:

Impressed! Looks very promising. Maybe you need to blacken it all too. Keep us posted.

Thanks Gorann, it will be fully blackened inside and out.

2 hours ago, globular said:

Looking very good 

If you're up for making more than just for yourself then I'd be interested in buying one or two. (Not for a RASA but for minimising back focus usage with binoviewers on an EdgeHD.)

@globular I’m able to build this because my camera has a 54mm threaded connection and I’ve been able to modify the rasa’s camera connecting plate to suit. It won’t work for a 48mm or smaller connection because there’s no support for the male thread into the camera.

To connect to your binoviewers I don’t know what connections are involved.

The metal for the filter drawer/slider arrived and I've had a play.

It proves that a filter will go between the rasa 8's mounting plate and a **camera with a 17.5mm back focus. I'm restricted to certain filters due to the filter's physical depth and that will probably alway be the case with mounted filters.

**(with my ASi2600MC Duo anyway).

I now need to go back and make a couple of minor alterations to the main body and to the slider. Add some finger grips to enable the sider to be placed/removed safely and a small magnet to act as a retainer so the filter remains in place.

A light blocker around the closure area to ensure there are no false gradients or patches generated across frames.

I also need to make a better holder to retain the slider whilst machining the 48mm filter thread. One which will stand up to making more than the single prototype.

TBC.

Thanks for looking.

55 minutes ago, Roy Foreman said:

Good to see the flame nebula displaying its true colour.  So many images don't capture the subtle yellows, particularly when filters are used.  Like you I always revisit the old favourites each year, but Orion is a bit too far east for my location at the moment.

It is for me Roy but it was 04:30 in the morning and Orion was high in the SE ! Best night I've had for months.

The flame and Horsehead is a single 300s sub and was the final single frame of the night as I just couldn't finish up without having a 'first' of the season image of the area. This is a slight crop for framing and used an IDAS NBZ filter during capture. Also a first use in PI of the GHS. Much easier to hold shadow detail but needs some time and lots more playing...

Veil area: 3x 600s, 3x 240s subs processed in PI this time trying the Narrowband Normalisation. Even more practice needed (for me) watched a few YT videos but my processing didn't really follow the videos....

Bubble area: 10x 600s subs, IDAS NBZ filter. Just followed my normal Curves Transform and Saturation routines for this one.

Noise reduction used on all images. Bubble and Veil images had the works (star removal (star and starless images processed separately and recombined), star reduction and noise reduction).

Thanks for looking

Two images from last night. Started with the M106/H2-Lemmon image shot in deepening twighlight. The Witch Head was at the other end of the night and shot circa 04:30.

Further data to come. Just thought I'd post.

Thanks for looking

After capturing 10x 10 min subs which all looked quite clean I was looking forward to the processing...

Somehow this heart looks more like a smiling, drunken skeleton.

Back to the drawing board. Live and learn!

Made me laugh though.

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!

28 minutes ago, Rodd said:

A dark which with an eagles face!

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...