zwo camera for use on RASA 11 Celestron

[h0ughy]

I have a few issues here, one is the use of a zwo 071 or 094 with the RASA but with a uvir filter in the train? so how am i going to achieve this?

[Merlin66]

https://astronomy-imaging-camera.com/products/asi-cooled-cameras/asi071mc-pro/

This camera seems to have a T thread front connection. It looks like ZWO also supply a M42 to M48 adaptor which would allow the use of 2" filters.
What about a 2" UV-IR filter???

How doe the camera attach to the RASA??

Correction: the camera has an M54 filter thread attachment.

[h0ughy]

this

[Merlin66]

Ahh OK, it's an T2 Thread attachment.

Somewhere (Telescope Express?) I've seen a T thread>filter>T thread adaptor. Hmmm but this might have been for 1.25" filters not 2" filters.

I'll look around.....

[JA]

Hello H,

It would surprise me if the manufacturer hadn't provided for the use of filters with their design and that sounds like what the M42 to M48 adaptor, that Merlin mentioned, might be about. Of course as per your drawing the camera has a M54 x 0.75 female thread so perhaps another adaptor is also required or an alternate mounting plate is available for larger format cameras. Perhaps question the manufacturer or your vendor directly for a solution.

Be that as it may, if you run in to difficulty with adpators/back-focus distance, etc.. AND if you are adventurous and you can only use the mounting plate you showed in the drawing, you could .....

fix an M48 female threaded ring (perhaps use a photographic filter 48mm stepdown ring) to the inside flat surface of the front conical mounting plate, which could serve as a mounting thread for m48 filters (albeit difficult to changeout). Of course this is all provided that it doesn't foul (contact) anything in the area on the telescope corrector. As a 48mm filter, with perhaps 44mm in open aperture, it shouldn't reduce or obscure the camera beyond what the telescope's own 37mm internal bore on the mounting plate already does. Diagram attached of above concept.

Best
JA

[Merlin66]

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p1791_Baader-M48-female-to-M54-male-Filterthread---2--filterholder.html

Then there's the M48 to T thread...
https://www.myastroshop.com.au/products/details.asp?id=MAS-005K2

Maybe??

[h0ughy]

will have to look at the options brought up

[JA]

If you have a look at the white paper for it, here:
https://s3.amazonaws.com/celestron-site-support-files/support_files/rasa_white_paper_web.pdf


There is a filter holder for a clear filter (see 1st pic) , which can be replaced by their own light pollution filter (I think possibly the one you purchased, not sure). In any event according to their specifications the thread for the filter is a very unhelpful M75 x 0.75 (see 2nd pic: Appendix A excerpt). Only problem would be finding such a 75mm filter size. 72mm and 82mm are a dime a dozen. Maybe a stepdown or stepup ring can be found or an extensive search.

Best
JA

[h0ughy]

i took down the rasa from the doghouse this afternoon and packed it away ready for SPSP.

But i did take images of the adapter that Celestron provided. the canon adapter was mine

[h0ughy]

i bought that but didn't realise it doesn't do the uv/ir

[bert]

I think you need this, and it allows you to use other filters as well.

https://www.baader-planetarium.com/en/filters/baader-ufc-s70-11%2214%22-rasa-adapter-telescope-sided.html

Brett

[h0ughy]

now i am thick but how does that one work:question:

[h0ughy]

can i leave the light pollution RASA filter i bought and just add a UVIR and screw on the camera above it?

[bert]

It replaces the adapter that comes with the scope. The existing filter stays where it is. It allows a filter drawer to be inserted between the rasa and the camera, it would also allow you to do Mono imaging with filters.

Here is a better page to view the system:

https://www.baader-planetarium.com/en/blog/baader-ufc-universal-filter-changer-the-ever-growing-filter-chamber/

[h0ughy]

have you ordered one yet for your setup Brett? which bits?

[bert]

Nah, I'm using a ASI1600 one shot colour. My system is remote so filters are out.

I have the primary focuser automated, but I'm still working on remote control of the focusing locks. I have some solenoids on the way, I hope they are going to work out for me.

[h0ughy]

i have a one shot as well but not the asi1600, however do you use a uvir?

[h0ughy]

I asked bintel why the asi camera doesn't come with an option to have the uvir installed from scratch. Makes good sense to me?

[Merlin66]

David,
The ASI 183MM came with a filter adaptor which screws into the front of the housing - for 1.25" filters.
https://astronomy-imaging-camera.com/products/accessories/t2-1-25-filter-adapter/

(Looking at it, it would probably also fit the ASI 174?)

[h0ughy]

well i am getting the ASI071 osc, thought about the asi094 but the vignetting would eventually become an issue for me. there is no room in my world for 1.25" filters;)

[JA]

Based on those images and the specified dimensions in the Celestron drawing, it seems like there would be no internal interference and that it would be a relatively easy modification as per my earlier drawing / proposal and allow you to use a wide selection of 2 inch / M48 filters.

Best
JA

[h0ughy]

I do agree but may have to see if it can be made

[bert]

Are you sure that the filter that comes with the scope isn't ir/uv blocked?

No, I don't. Thats more a refractor thing for me, to minimise CA. Because I'm one shot colour, the uv and ir would likely be blocking those wavelengths anyways. even if they are not, I don't really care.

[h0ughy]

Not sure

[h0ughy]

The filter info is here but haven't clue what is what

[Merlin66]

David,
That's a light pollution filter, but also has UV/IR cut-off.

Looking at the QE curve of the sensor, I'd think you'd probably need a UV/IR filter to reduce star bloating.

[h0ughy]

Fantastic to see someone can understand that. With a coloured crayon can you show me where it falls short? Thank you for pointing that out :thumbsup:

[Merlin66]

No coloured crayon required....
The transmission curve drops to zero below 4000A and above 7000A. Therefore no (!??) transmission in these areas.

My comment re UV/IR filters was as an alternative to this light pollution filter (this filter, besides cutting out unwanted light also cuts out some useful light.)
Sorry if there was some confusion.

[h0ughy]

So I can just use the RASA light pollution filter and should be OK?

[Merlin66]

Yes.
This would work fine as a starting point.
Ken

[h0ughy]

awesome - the ASI071 arrived today - ended up getting this second hand saving a few hundred off a new one

[h0ughy]

next piece of the puzzle arrived today - the astrozap dew shield especially for the RASA. now i am getting it together i am coming down with a cold, the other reason apart from cloud why i am not at Wiruna today for SPSP.

its a quality product - apart from me:lol: snot everything is equal:rofl:

:help:

[h0ughy]

between the cloud i managed to get focus of the RASA with the ASI071. this is without darks and bias and flats. its just 5 x 1min at 0 gain camera set at -5deg C. the RASA light pollution filter is fitted
processed in Pixinsight but i noticed the focus was out slightly

[LewisM]

Dave, your full name and address is in one photo of the box. Might want to censor that.

Nice initial shot!