ASI290MM ( not mini) as Guidescope camera

[Startrek]

Im considering buying the ASI290MM USB3 ( not the mini ) as a guide-scope camera due to the smaller pixel size ( 2.9uM ) from that of my current ASI120MM-S ( 3.75uM) which would effectively bring my imaging/guiding image scale ratio from 1:4 down to 1:3 on my existing rig.
Comments from other forums suggest the 290MM is a more sensitive camera for guiding purposes and performs well up to imaging focal lengths of 1500mm

I welcome comments from folk who use this camera in their guide scopes with longer focal length imaging ( say 900mm to 1500mm fl )

Thanks

[ChrisV]

WeI've got one. Used to used it for live imaging. Now used mostly as a guide camera with a guidescope on the scopes listed below. It's a great camera. Very clean and sensitive. I've also had a 224mc - much better than that

[Startrek]

Thanks Chris
Appreciate your info
The smaller pixels are what got my attention on the 290MM at 2.9uM
I have a 10” f5 Klaus Helmerich carbon fibre newt on order so I’m confident that a guide scope arrangement will work in lieu of OAG so long as the guide scope is mounted rock solid on the OTA, tubes rings at 480mm apart with Losmandy bar and my imaging / guiding image scale ratio is 1:4 or better. The ratio on my current 8” f5 newt is 1.4 with the ASI120MM-S and my PHD2 guiding on the EQ6-R is now at 0.60 to 0.70 total rms
The 10” f5 will be sitting on a new EQ8-R pro mount in my NexDome Obs down south

Big mid year upgrade !!

The 8” f5 will still be used for the medium to bigger nebula, the 10” for galaxies , globs , and smaller nebs

Cheers
Martin

[Kuz]

Hi Martin.

I have both 120 mini and 290 mini version currently used as guide scopes, and for me the 290 mini is 10 times better than the 120 mini. In my opinion. I have used the 290 in my esprit 120 and it seemed to go alright , but was only seeing what it could do didn't real take many images.

[Startrek]

Kuz,
Thanks for your experiences
Yeh the 290MM with smaller pixels will be more sensitive and also lowers your image scale ratio to your main imager.
So it’s a win win
I would be buying the Standard 290MM not the mini ( same sensor in both ) as I’m going to utilise my existing USB3 cabling system , the mini used USB2C interface
Thanks again
Martin

[The_bluester]

I have been using the 290MM mini for a couple of years and they (I have two) have performed very well either coupled up to guidescopes (A 72mmm Evostar) or in an OAG at focal lengths from about 300 to 2300mm. At 2300 (Celestron C925 at it's native F10) I binned it 2X2.

As far as I know there is no functional difference between the MM and the MM mini, just the mini is easier to package for use with an OAG.

[Dennis]

Hi Martin

Here is the trail of Nereid, one of the fainter satellites of Neptune at mag. 18.69 auto guided with the ASI 290 MM USB3 Model.

Images taken with a Tak Mewlon 210 F11.5, Tak Reducer/Flattener x0.8 and ZWO ASI 294 MM camera from our back garden in suburban Brisbane, under Bortle class 6 skies on 5th Oct 2021.

The ASI290MM was fitted to a PrimaLuce Labs 60mm, 240mm fl guide scope and the Mewlon was imaging at around 2000mm on my Tak EM200 Temma II Mount.

Cheers

Dennis

[Startrek]

Paul,
Thanks
All positive feedback
Cheers
Martin

[Startrek]

Thanks Dennis
Very impressive result
Also impressive rig
Looks like the 290MM needs no further research or reviews
Cheers
Martin

[Startrek]

Dennis,
I noticed your using the Prima Luce Lab 60mm guide scope 240mm fl which have support rings not clamps
I’m surprised your getting such great guiding at 2000mm fl with support rings ?
I’m currently using an Orion 60mm guide scope with support rings but only imaging at 1000mm ( 8” f5 GSO newt ) guides around 0.60 to 0.70 total rms
Folk have advised to choose support clamps in lieu of rings to minimise movement and differential flexure when imaging over 1000mm
Obviously your kits working well
Any further comments on the type of Guide scope
For my new scope arriving in May ( 10” f5 KH carbon fibre ) I was considering a Williams Optics 61mm GuideStar Guide scope 320mm fl which has clamps and only weighs 1.4kg ( new mount as well EQ8-R in my NexDome )
Martin

[Dennis]

Hi Martin

The PL 60mm F4 (240mm FL) with rings is a recent purchase and I have only managed to use it 4 or 5 times due to poor weather, lack of time, etc. and so far it appears to have worked well with the PL Guide Rings. It is a very light OTA.

The PL Guide Rings are bolted to a DIY aluminium plate, which is itself bolted to some Tube Rings, so it is a reasonably rigid connection.

The PL 60mm actually replaced a very old WO 66mm Petzval, which I think was 400mm FL but it was very heavy. I had this mounted in tube rings bolted to the Mewlon Tube Rings, so I have been pleasantly surprised with the PL 60mm F4 on the Mewlon thus far.

I have read that modern autoguiding algorithms allow a ratio of 1:10, but where possible, I like to keep below this, between 1:8 and 1:5.

I am a sporadic imager, so I don't have a lot of mount data to look back on, but from memory, the Tak EM200 was guiding at 0.3 to 0.4 RMS according to The Sky X Pro.

I set up and tear down each night and have just started using T-Point in The Sky X Pro. I run a 50 point model each time I set up. I use the QHY PoleMaster for PA.

The EM200 does not have PEC but I think T-Point and ProTrack in TSX Pro have probably helped with my auto guiding, they have certainly absolutely helped with pointing accuracy.:):thumbsup:

Cheers

Dennis

EDIT: Added photo showing PL 60mm and its Red Tube Rings.

[Startrek]

Thanks Dennis
Appreciate it
Maybe I’m getting too obsessive over my future set up in particular guiding
I’m only going to be imaging at 1250mm but the 10” OTA is quite long at 1150mm.All I can do is bolt everything down rock solid on the new monster mount and hopefully it will all work out in the end
Cheers
Martin