12 replies to this topic

[GKA]

I recently bought a Vixen GP mount on a pier for a great price , and on it there was the above mentioned telescope ( i think these were sold as a package.).

I think , they also may have been called Europa ?.

After my search i have found out that its F 4.8.

So , the telescope looks like its from the 90's era , maybe the beginning of 2000.

The telescope looks shabby , the focuser needs fixing , but the mirror is flawless.

It has no resale value , and i don't really need another scope , but i will fix the focuser and try it out.

And if it turns out good , i might upgrade it with a new focuser , and use it in my observatory on certain targets.

So , does any of you gentlemen have any suggestions for a focuser upgrade , and other upgrades i can do to this?

I believe it's full name is Orion Optics 250GX (Europa).

Here's a link to an old review :

 

http://www.users.glo...d/newtonian.htm

[Dobs O Fun]

Bump..

Anyone can help here with a suggestion for a focuser upgrade?

[Demon]

Just spotted this, I recently was given an old orion 250gx. I have drilled the back and fitted a cooling fan and swapped the focuser to a standard dual speed gso Crayford (rebranded by many including meade) however i didnt need to redrill so pretty standard hole pattern. There's fancier options but it works well for me. I'm using it for imaging with an autofocuser and it's working great. The only aspect I'd check if your thinking of using it for imaging is check your secondary size and focal point. I fitted longer primary cell central fixing bolt and longer collimation bolts in order to raise primary, get focal point further out and fit a filter wheel after focuser. My secondary was large enough to not give vignetting without changing it, however I'm not sure it hasn't been changed previously. So main first question is visual or imaging and that will determine what you need to work out...

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Edited by Demon, 24 April 2025 - 04:35 PM.

[Demon]

All that said I've just looked at the review you linked to and it looks like I've got a different variant of 250gx. Mine had a different focuser base (square) albeit a pretty poor rack and pinion. Mine gas a 3 vane spider. However at the end of the day if you need to just redrill if focuser holes are different as just thin steel. But same first question applies visual or imaging...

[GKA]

Bump..

Anyone can help here with a suggestion for a focuser upgrade?

Thanks.

[GKA]

All that said I've just looked at the review you linked to and it looks like I've got a different variant of 250gx. Mine had a different focuser base (square) albeit a pretty poor rack and pinion. Mine gas a 3 vane spider. However at the end of the day if you need to just redrill if focuser holes are different as just thin steel. But same first question applies visual or imaging...

Thanks for your reply .

Yes , i believe my GX250 is an older model , and yes , i will have to drill new wholes.

Before i make any investments in this , i will test it visually.

I have taken the very simple focuser apart , cleaned and regreased it , and put in some new set screws , as the old ones were broken.

Hopefully this will give me a chance to find out if it's a good or bad sample.

Sadly there are no center dot on the primary mirror , so i  cant check the collimation on the secondary , but i can check an collimate the primary.

If it checks out good , i will use it mainly for astrophotography  on my NEQ6 in my observatory.

My speciment has only two spiders , and a simple focuser which is very solid , but not of the best.

I have looked at the Gso focuser , but also the monorails from Ts optics , and the Baader steeltrack , since both of these have adapters.

I will also order a kit with centerdots and template.

Here's my focuser , it is very shiny inside:

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[Demon]

I'm sure that would be fine for some visual, however probably upgrade for imaging. A friend who is a top imager has a steeltrack and if you've plenty of funds then easy decision. My older gso has no thread for direct mounting but does me well. It's easy to add a centre circle to the primary as collimation is critical ( an use a diy camera based collimator like an ocal rather than a laser and cheshire). Also making sure your mirror gets to and stays within a degree of ambient when imaging. However I don't think you'll be disappointed. The guy who gave me mine is shocked at what I'm getting from mine as before it was just sat there gathering dust and her just bought a doublet. I had to remove my 16" as it was to prone to breezes but this is a little beauty and my imaging has only improved. But check your secondary size and where focus is before drilling a new focuse r on, just in case you need to move spider and focuse r down as opposed to moving primary up.

Edited by Demon, 25 April 2025 - 02:06 AM.

[Demon]

 Heres a few that were taken with my 250GX, please excuse the dirty optics and no flats...

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[Demon]

A few more with 250GX...

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[Demon]

Last one (a quick recent play on the Leo Galaxy Cluster)...

p.s. I dont get the most out of it as I need to up my integration time and processing skills and my main camera doesnt even have a cooler currently.

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Edited by Demon, 25 April 2025 - 02:57 AM.

[Demon]

Dug out some more photos...

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[Demon]

PS yep, collimate then do a defocused star test to confirm how good your mirrors are. Then you can proceed accordingly...

Edited by Demon, 25 April 2025 - 03:26 AM.

[GKA]

Very nice pictures , and i liked the horsehead very much. , yes i will measure my mirror when i take it out for "dotting".

As for a new focuser , if i find the telescope good , i will save up the extra for the steeltrack or another quality focuser , but i think i will buy the kit with dot and template first , so that i can dial in the collimation.

Thanks for the tips.

I'm sure that would be fine for some visual, however probably upgrade for imaging. A friend who is a top imager has a steeltrack and if you've plenty of funds then easy decision. My older gso has no thread for direct mounting but does me well. It's easy to add a centre circle to the primary as collimation is critical ( an use a diy camera based collimator like an ocal rather than a laser and cheshire). Also making sure your mirror gets to and stays within a degree of ambient when imaging. However I don't think you'll be disappointed. The guy who gave me mine is shocked at what I'm getting from mine as before it was just sat there gathering dust and her just bought a doublet. I had to remove my 16" as it was to prone to breezes but this is a little beauty and my imaging has only improved. But check your secondary size and where focus is before drilling a new focuse r on, just in case you need to move spider and focuse r down as opposed to moving primary up.