Polemaster for planetary / deep sky? It's possible!

[MarkW]

What's the backfocus anyone is finding when using with an off axis guider.  For me it seems i need a C=.1.25 adapter that is really short. 

[Jannis]

I have not used the polemaster as an off axis guider, however, considering it's using a standard CS mount lens it should have the same back focus as the QHY5L-II i would guess?

If so, I'd guess the back focus is 12.5mm. Or is this different when using an off axis guider?

This is the lens type the Polemaster originally comes with:

Specifications:
Focal Length: 25mm
Angle of View: 11°
Distance of View: 70m

Image Format: 1/3", 1/4" 
Mount: CS
Aperture: F1.2

Suitable for cameras with either a 1/3" or a 1/4" sensor.

[newbie alert]

Polemaster fov is way wider than a qhy5l-11,they're both uncooled so using for deep sky is unlikely to do the same job as a cooled ccd..qhy5l-11 for planetary yes as that's what it was designed to do..polemaster...ummm....like I say fov is too wide..

[Jannis]

I dont think you read the entire thread... :-) 

The sensor is the same, and the lens is easily removed. I have used it even for narrowband with better success then the 5l due to no FPN removal, meaning my calibration frames actually works. its unfortunally limited to 120 sec exposures though..

[cbbella]

On 18/03/2017 at 17:53, Jannis said:

Yes, removing the lens leaves the sensor unprotected. There is no protection glass on the Polemaster, so i'm using a simple UV/IR-block filter on my C Mount to 1.25" adapter. 

hi, do you have a link to the filter you use or one similar.  i have filters but they only have a thread on one side whereas yours has a thread on the outer part as well.  i'd like one like yours as i have an adapter to fit my 9x50 finderscope that i could thread my polemaster onto to guide with and use my qhy5l-ii colour camera to image with but i can't seem to find a filter with threads on either side

[Jannis]

Hi,

Sorry for the late response. I'm not sure if i understand exactly what you mean. Are you talking about the inner threads in front of the 1.25" filter?
I'm trying to remember where I've bought it, but I honestly can't remember for sure. I've only ever bought two 1.25" IR/UV filters, one together with a webcam, and one from e-bay with the 1.25" adapter for the Polemaster.
 

 

[cbbella]

Yes I am on about the inner threads so I can screw it onto my finderguider adapter and then use my QHY5L-II Colour camera for imaging. I have filters but none have inner threads like yours.

 

[iapa]

Very rude of me, but I notice I did not reply to confirm that I was successful, following the instructions posted earlier, using this as my guide camera.

[Jannis]

cbbella: That adapter appears to be a finderscope to C mount adapter, not a finderscope to 1.25" adapter. To use it with either the Polemaster or QHY5L, simply remove the already attached C/CS mount to 1.25" adapter (C/CS mount lens for the Polemaster) and screw camera on directly. You won't be able to use any 1.25" filters together with that adapter, but neither is it needed (you will get bloated stars without the IR filter on the finderscope, but this will not affect guiding accuracy).

iapa: Glad to hear you got it working! :)

[cbbella]

19 hours ago, Jannis said:

@Jannis: many thanks for that info

[newbie alert]

On 14/10/2017 at 11:01, Jannis said:

I dont think you read the entire thread... ?

The sensor is the same, and the lens is easily removed. I have used it even for narrowband with better success then the 5l due to no FPN removal, meaning my calibration frames actually works. its unfortunally limited to 120 sec exposures though..

Sorry no I didn't read the whole thread..any images to show it's potential please?

[Jannis]

 Sure! These are at least some of my images so far where I've used the Polemaster only, or for Ha and/or L data.

Cygnus HaRGB. Polemaster for Ha, RGB from 550D:

Fireworks Galaxy LRGB - L from PM, RGB from 550D:

M63 Sunflower Galaxy LRGB - L from PM, RGB from 550D:

M51 LRGB - L from Polemaster RGB from 550D:

M13 LRGB - L from Polemaster, RGB from 550D:

Bubble Nebula LRGB - Polemaster only:

Eagle nebula HaRGB - Polemaster only:

NGC 2841 LRGB - L from Polemaster, RGB from 550D:

NGC 2903 LRGB - L from Polemaster, RGB from 550D:

NGC 2403 LRGB - L from Polemaster, RGB from 550D:

[newbie alert]

Wow..looks like you been having some fun with it..thanks for sharing info and images..

[newbie alert]

Nice images..just in the process of trying mine for guiding..preferably oag.. but I'm stuck on how to convert the top to a 1.25 fitting and it won't connect to phd2

Any ideas,and pics of the connector/adapter?

Thanks in advance..

[Jannis]

You need a C-mount to 1.25" adapter, something like this should work: https://www.ebay.com/itm/C-Mount-to-1-25-Video-Camera-Barrel-Ring-Adapter-for-Astronomy-Telescope-CO/202366475568?hash=item2f1dfb5d30:g:QbEAAOSwCGVX5KLr

Unscrew the cover, unscrew the lens, attach the adapter and you're ready to go.
For sensor protection i also recommend a filter of some sort. UV/IR for refractors, while clear glass should be fine for reflectors.

If PHD can't connect to camera ("QHY not found"), it's probably because you use a driver that's too new. Try installing v. 1.44 and see if it detects camera. I've shared the old driver here: https://www.dropbox.com/sh/ilmsot3rgeg99bn/AADv7oR0W4oVmLq0NfWtENs0a?dl=0