T2/M42 rotators

[The_bluester]

I have done a bit of searching today but not really proven much. Does anyone know of good T thread rotators (Male to female or female-female) for mountings camera? I have worked out that as I have it positioned now on the ED72 I can not see the shadow of my guiders pick off prism even when it is aligned with the short side of the sensor. That makes camera rotation relatively simple as I can rotate it after the OAG so camera rotation will not require guiding re-calibration.

The most common T thread rotator I have found is about 5.5mm thick and looks like tilt city to me. Does anyone know of any around the 20-25mm thick mark that are rock solid to mount a camera on?

[glend]

Have you looked through the TS page of rotation adaptors. Seems like they cover several options.

https://www.teleskop-express.de/shop/index.php/cat/c133_360--Rotation-and-Quick-Changer.html

And given the short focal length of that scope, a small guide scope gives you much more in the way of options. Why complicate it?

[The_bluester]

The only T2 one they show on that page is the 5.5mm one which looks very likely to be tilt prone to me. A few searches indicated that was the case, even to the extent of tilt changing depending on where in the sky you are pointing.

I will add the caveat, I am browsing from the phone as our net provider has a major outage today so I could miss things.

[AstroApprentice]

Hi Paul,
I have used the 5.5 mm T2 rotator and don't really like it. https://www.teleskop-express.de/shop/product_info.php/info/p5547_TS-Optics-T2-Thread-360--Rotation-and-Quick-Changer---5-5mm-short.html
The threads are necessarily very short, so I don't have confidence with it holding expensive gear, plus I don't like the way the thumb screws dent the track when tightened. The track also wobbles a bit when rotating.
You could also use a Baader quick changer https://www.baader-planetarium.com/en/accessories/adapters-imaging-accessories/astro-t2-system/baader-heavy-duty-t-2-quickchanger-(t-2-part-06a).html
I have one on my binoviewers, it's OK to rotate, but not really ideal for what you want.
By far the best rotator I have used is a Borg:
https://www.sciencecenter.net/hutech/prices/borgparts/html/7352.htm
I wish they made it in T2 rather than M57 thread as it is incredibly smooth to rotate and nothing moves when tightening thumb screws. Borg sell M57-T2 adapters that you could use on either side with minimal increase in path length, but the rotator, plus two adapters will work out very expensive. Superb quality at a very high price for what you need. There's definitely a market for a T2 version of it...

[The_bluester]

Actually the Baader is the one I am considering. Whichever setup I am using I have space in the imaging train for it, before the OAG for the SCT (As the prism does come in to view if not aligned with the long side of the sensor) and after for the ED72 as the prism does not show on it at all.

[Joshua Bunn]

Hi Paul,



I'll have a go at making you one, always up for a challenge and something different :) If you're interested, send me a PM and we can go from there.


Regards
Josh

[The_bluester]

I am sitting on the idea for a little bit, it is not a great issue on the ED72 as it is pretty easy to rotate the whole tube in the rings.

See how things look once that adapter you are doing for me to properly mount the reducer is on it.

[Joshua Bunn]

No worries Paul :thumbsup:

[billdan]

Gooday Paul,

If you want to spend some bucks ($US600), Rigelsys has an electronic rotator which is ASCOM compatible (tested OK with SGP) and the USB controller supplied controls focusing as well.

https://www.cloudynights.com/topic/608573-coming-soon-nframe-camera-rotator/

Cheers
Bill

[AstroApprentice]

FYI,
I came across this M48 rotator:
https://www.pierro-astro.com/materiel-astronomique/accessoires-astronomie/accessoires-m48/bague-rotative-m48-hq-tirage-12,5mm_detail

Artesky also make M54 version:
https://www.telescopi-artesky.it/en/artesky/adattatori-m54m68m69etc/4298-rotatore-m54-360-artesky.html?search_query=rotator&results=2

[The_bluester]

I actually have one of the Baader ones on the way (Hopefully receive it today) with potential to modify it if required to reduce back focus usage. I can't open the second link but the issue I see in most of the slimmest ones is the likelihood of introducing tilt when rotating. Have to see how I go with the one I have coming, if it works I just have to buy a second example of one or the other part of it to be able to use it as a quick changer to have easy movement of the camera between scopes as well as rotation.

[The_bluester]

Looking again, that first one (I can't open the link for the 54mm one) might actually be a good thing if tilt is well controlled and the Baader one I have coming would work well on my SCT for the price of unscrewing either one from the OAG to change scopes.

[AstroApprentice]

Not M42, but for anyone interested, these M72 & M92 manual rotators certainly look high quality:
https://lbastro.it/en/product-category/rotators-field-manuals/?v=6cc98ba2045f

[The_bluester]

My Baader one turned up yesterday (after a trip with Auspost that averaged under 5KMH time for distance!)

It looks like a nicely made piece of kit. What I need to do now is work out if I can stack it in front of my TOAG with the guide cam in focus in a way that gives me well corrected stars with the ED72. If so I can fit it in front of the TOAG and buy a second compression clamp part for it (They are available separately) that I can put on my SCT to make both work with it.

If not I have to see if I can set the TOAG prism on the corner of the sensor out of the light path but still get useable guide stars when using my SCT. That would actually be really handy as it would allow me to rotate the imaging camera without rotating the guider. Framing change with no need to re calibrate PHD2!

Those ones above look nice!

[AstroApprentice]

I contacted Luca at Artesky and he said he will soon produce a T2 (M42 p0.75) version of his rotator. I’ll be ordering one.

[The_bluester]

I am actually a bit tempted to get one of his M48 ones to try with the ED72. It uses 3mm less backfocus than the Baader to begin with but being M48 it would remove a couple of adapters and potentially save more backfocus than that as well. Could be as much as 5 or 6mm between the reducer and sensor.

I can't quite get the Baader one in between the ED72 reducer and the guilder while still being able to achieve focus on the imaging camera AND have the guider close enough to parfocal with it to use. On the SCT it would be a snap as I am not using a reducer on it now and it has oodles of backfocus to play with.

[AstroApprentice]

The M42 rotators are now in stock at Artesky:
https://www.telescopi-artesky.it/en/artesky/adattatori-t2/4389-rotatore-t2-360-artesky-8055517130360.html?search_query=rot atore&results=3

Thickness extension: 12.5MM
M42*0.75 external thread: 3MM
M42*0.75 internal thread: 5MM

[AstroApprentice]

Here’s a link to the Aus distributor:
https://www.siderealtrading.com.au/product-category/artesky/

[The_bluester]

I actually bought the Baader one and currently have it fitted between the OAG and imaging camera which is a handy location. On the ED72 I can get good guide stars with the prism in any location around the sensor without it casting a shadow in the image, so I am able to rotate the imaging camera freely without having to re calibrate PHD2.