Off-axis guider? Considerations and suggestions?

[turboscrew]

Hint to @SkyHiker too...

You can, probably, save some millimeters by using these:

9 mm OAG
https://www.teleskop-express.de/shop/pr ... -9-mm.html

Zero-length adapter OAG/T2
https://www.teleskop-express.de/shop/pr ... OAG16.html

Zero length adapter T2/OAG
https://www.teleskop-express.de/shop/pr ... short.html

Thanks, it may help but so long as my stars are round I won't worry too much about it. BTW I have two 48x42 mm adapters (your last link), IIRC they come with the ASI2600s that I have. And one of them is inside my MM configuration. The other one may be in the MC, I need to check.

The idea is the with those adapters, you get 9 mm T2/T2 OAG.
Just, because I remember that you had 1 mm too much in-between. :wink:

[turboscrew]

Ordered ASI294 MM pro mono.

BTW, about the crystals: Abracon AB308 16MHz, radial:
Operating Temperature -10 +60 ºC
Storage Temperature -40 +85 ºC
Frequency Stability over the Operating
Temperature ( ref. to +25°C) -50 +50 ppm
https://www.mouser.fi/datasheet/2/3/ab308-47627.pdf

I think I'll get ZWO EFW 8x1,25" (31 mm unmounted).
That should not be a problem according to astronomy.tools, and I could use 1.25" filters with my planetary camera.

But does anyone know if this OAG is good?
https://www.teleskop-express.de/shop/pr ... -9-mm.html

[yobbo89]

But does anyone know if this OAG is good?
https://www.teleskop-express.de/shop/pr ... -9-mm.html

you are going to use your Omegon Camera veLOX 178 C to guide with ? you will need some sort of c mount attachment or 1.25'' holder, that oag seems to be t2 conection (42mm x 0.75mm) on the guide cam connection . your omega cam is 1.25'' with a cmount threaded connection .

so you might need an adapter or a small helix focuser, it seems henk has something like this on his oag ,to have something else to focus with is alot better then moving the pick of up and down as this methode is realy limited and the futher you move it out the worst the guide stars are due to coma .

i think a short t2 to 1.25'' helix focuser will work well with that oag .

as for the zwo filter wheel . hmm , i live in the tropical state here with alot of dew ,both my zwo fw sometimes build up moister and sieze, the motors are exposed for what ever reason ... i typicaly put a dab of thin oil on the motor and blast them with hair dryer after ever image session . doing this has stop them siezing , just something to look out for with these filter wheels , having a dew heating on them might be necessary depending on your climate ..

[turboscrew]

But does anyone know if this OAG is good?
https://www.teleskop-express.de/shop/pr ... -9-mm.html

you are going to use your Omegon Camera veLOX 178 C to guide with ? you will need some sort of c mount attachment or 1.25'' holder, that oag seems to be t2 conection (42mm x 0.75mm) on the guide cam connection . your omega cam is 1.25'' with a cmount threaded connection .

so you might need an adapter or a small helix focuser, it seems henk has something like this on his oag ,to have something else to focus with is alot better then moving the pick of up and down as this methode is realy limited and the futher you move it out the worst the guide stars are due to coma .

i think a short t2 to 1.25'' helix focuser will work well with that oag .

as for the zwo filter wheel . hmm , i live in the tropical state here with alot of dew ,both my zwo fw sometimes build up moister and sieze, the motors are exposed for what ever reason ... i typicaly put a dab of thin oil on the motor and blast them with hair dryer after ever image session . doing this has stop them siezing , just something to look out for with these filter wheels , having a dew heating on them might be necessary depending on your climate ..

I already have T2 adapter for the velox. 19 mm altogether from T2 to the sensor of the velox.
My plan is to use velox as both guide and planetary camera.
Now it's good time to plan, when the weather is terrible and the mount is in Germany to be fixed.

Thanks for the heads up about the motor.
I don't know if I can say anything general about the weather. This morning it was -21°C, now (after work) -5°C.
Got to check if the pipes in sauna are frozen again...

[SkyHiker]

Now is a good time indeed. Last summer would have been better.

About the Velox and that OAG, it looks like another problem to be solved. First, what guiding frequency can you achieve with the Velox? It is a color camera so image transport takes longer than with a mono. The ASI120MM mini is quite cheap, and fits into a simple QHY OAG M without having to look for more adapters and a focuser for that rather barebones looking OAG. I would just take the easy route, the items I mentioned are no financial burden here at least. I have to say the ASI120MM mini is a bit noisy but good enough IMHO, not a bottleneck.

I recommend that you start building a rig that has all connectivity and data acquisition right by the camera, like the Medusa rig I built. Forget about that old laptop. You can use either a Pi4b with Astroberry or a Windoze mini PC running Nina with at least 2 USB3 ports. Get a powered USB2 or 3 or C hub and 12 to 5 V DCDC as needed to get enough power.

The reason is that this makes setting up a lot easier, remote control in freezing temperatures too, but also, having everything in one small package you can build an enclosure with a heating element in it like a light bulb or something else to protect against too low temperatures. Trust me, setup has to be easy because it is a drain on enthusiasm especially when going through practice sessions experiencing failure after failure. There is light at the end of the tunnel but it will take a while.

[turboscrew]

Now is a good time indeed. Last summer would have been better.

About the Velox and that OAG, it looks like another problem to be solved. First, what guiding frequency can you achieve with the Velox? It is a color camera so image transport takes longer than with a mono. The ASI120MM mini is quite cheap, and fits into a simple QHY OAG M without having to look for more adapters and a focuser for that rather barebones looking OAG. I would just take the easy route, the items I mentioned are no financial burden here at least. I have to say the ASI120MM mini is a bit noisy but good enough IMHO, not a bottleneck.

I recommend that you start building a rig that has all connectivity and data acquisition right by the camera, like the Medusa rig I built. Forget about that old laptop. You can use either a Pi4b with Astroberry or a Windoze mini PC running Nina with at least 2 USB3 ports. Get a powered USB2 or 3 or C hub and 12 to 5 V DCDC as needed to get enough power.

The reason is that this makes setting up a lot easier, remote control in freezing temperatures too, but also, having everything in one small package you can build an enclosure with a heating element in it like a light bulb or something else to protect against too low temperatures. Trust me, setup has to be easy because it is a drain on enthusiasm especially when going through practice sessions experiencing failure after failure. There is light at the end of the tunnel but it will take a while.

The velox 178C:
Size of chip (mm) 7.4 x 4.9
Chip - Diagonal (mm) 8.9
Pixel size 2.4
Resolution Photograph (Pixel) 3096 x 2080
Megapixel 6.4
Bit depth (Bit) 14
Images per second 59 (at full resolution)
Colour camera yes
Active cooling no
Power supply 5 (USB)
Interfaces USB 3.0, ST4
Autoguider yes

And my astro-laptop is not that old. Bought it this autumn. It's semi-rugged, and should take -30°C (-22°F) and light drizzles.
https://laptopmedia.com/review/acer-end ... eun314-51/

[turboscrew]

Just ordered the 9 mm OAG and the adapters I linked in post #39.
The filter wheel that I think I want (ZWO EFW 7x36), after all, doesn't seem to be available to me at the moment.
On the other hand, I've already spent about 2500 eur this month... Starts to hurt...

And I need the OAG to figure out what kind of extensions I'll need for the guide camera. The specs didn't tell the optical length in the guide camera direction.

Just got a mail from Germany about my mount. They still wait for colder weathers to get it tested.