Will I see stars to guide through an OAG using ASI 290 mini on an EDGE HD 8? - Forums

Topic starter

Oct 26, 2021 · Edited: Oct 26, 2021

I have an EDGE HD 8, and going to order an ASI 290 mini for a ZWO OAG (small mirror). Please let me know if I ll be able to guide with that setup. I mean… am I going to see any stars to guide? Please let me know if you had any success with that setup. My main camera is an ASI 533 MC PRO.
I just want to save some money, if I can avoid the common sollution of an expensive ASI 174 mini, and a Celestron OAG L.

It would be very helpful if you let me know of your experiences. Even If I achieve star to guide, will it be a good guiding?

James

Oct 26, 2021

I tried using an asi224mc with my Edge 8/zwo oag combo. The narrow fov made it difficult to find suitable guide stars in some areas of the night sky.

I switched to an asi178mm. The 178s sensor is large enough to utilize the entire image circle of the zwo oag.. and finding guide stars has generally not been a problem.

I suggest something with a sensor at least as big as a 178. My 224 has a similar fov as the 290 and it's too small IMHO.

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xordi

Oct 26, 2021

I have Edge Hd 8 and I used ASI120 and a very similar Atik guidecam and it was challenging many times to find a star. Often I needed to change composition because there was not any star in the specific area. The real gamechanger was buying Lodestar X2. Since I have it no issue with guiding.

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Rishi

Oct 27, 2021

I used to have problems sometimes until I got the 178MM Mini Mono. Now I do not have an issue. I must admit I am using a Celestron OAG that has a larger prism but I usually have so many stars that I don't think your slightly smaller prism will matter.

Scott Badger

Oct 27, 2021

Not much to add, but i’m also using the 178 mini with a zwo oag on a 9.25 edge and though I occaisionally only get a few, so far there have always been some stars to choose from.

Cheers,
Scott

Giannis Pomonis

Topic starter

Oct 27, 2021

So is the ASI 178 MM better than the ASI 290 mm mini. Does it have enough room to adjust the focus on the OAG? Will the ASI 178 be a good match for my EDGE HD 8?

Roland Gooday

Perfect post

Oct 27, 2021

Hi, I have the 178mm and the Edge 8" and always find stars, however I can't use it with the 0.7x reducer as it won't travel inwards enough (I have the celestron OAG). I imagine the 174 mini solves this problem. I started out using a smaller sensor colour camera (120MC) but rarely found stars.

Michel Makhlouta

Oct 27, 2021

Giannis Pomonis:
I have an EDGE HD 8, and going to order an ASI 290 mini for a ZWO OAG (small mirror). Please let me know if I ll be able to guide with that setup. I mean... am I going to see any stars to guide? Please let me know if you had any success with that setup. My main camera is an ASI 533 MC PRO.
I just want to save some money, if I can avoid the common sollution of an expensive ASI 174 mini, and a Celestron OAG L.

It would be very helpful if you let me know of your experiences. Even If I achieve star to guide, will it be a good guiding?

I have the same setups and I don't have any issues both at F7 or F10, with exposure times down to 0.5s even. 290MM mini, zwo oag (8x8 prism). There are some areas in the skies where the field is a bit empty and you might need to rotate to find a proper star, but I've never had this issue.

The 224MC and orion SSAG were a terrible experience with the EHD/OAG configuration

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Stephen Lamontagne

Nov 12, 2021 · Edited: Nov 12, 2021

Giannis Pomonis:
I have an EDGE HD 8, and going to order an ASI 290 mini for a ZWO OAG (small mirror). Please let me know if I ll be able to guide with that setup. I mean... am I going to see any stars to guide? Please let me know if you had any success with that setup. My main camera is an ASI 533 MC PRO.
I just want to save some money, if I can avoid the common sollution of an expensive ASI 174 mini, and a Celestron OAG L.

It would be very helpful if you let me know of your experiences. Even If I achieve star to guide, will it be a good guiding?

I use a ASI290mm mini on my EdgeHD8 but I'm using the celestron oag. I never have had to hunt for stars to guide on with this setup at f7 or f10.

*edit* I wanted to add that I'm located in Bortle 3 skys in Western Maine which I would imagine helps a bit.

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NuclearRoy

Nov 13, 2021 · Edited: Nov 13, 2021

I am using the 290mm-mini with a Celestron OAG and have always found a guide star with or without the 0.7x reducer on an Edge 8.
I'll agree with a previous poster in that I needed to rotate the OAG occasionally, for really empty areas. A bit of a pain to have to recalibrate PHD, but it was only occasionally.
No personal experience, but Loadstar folks seem to love them.

OK, I'll add that I'm in bright suburban skys near a mall and Shell cracker plant. Pretty bad

Wes Schwarz

Nov 13, 2021

Does anyone bin the 290 or use an inline .5x reducer?

Stephen Lamontagne

Nov 13, 2021

Wes Schwarz:
Does anyone bin the 290 or use an inline .5x reducer?

I bin the 290 when using it in the oag on the Edge 8.

AstroDarkSky

Nov 13, 2021

I have found binning the guide camera at 2 in phd2 gave me more star options to pick from and tightened their cores. Although, I still had to be careful with the binned stars being too dim and vulnerable to seeing shifts so it is kind of double edged. More stars to pick from when binned but you have to be picky which ones to trust basically

This was with Celestron OAG on Edge 9.25 but it probably would apply here too?

I will say I can rarely recall a time where I saw zero guide stars to choose from, but the choices are definitely noticeably limited when compared to non-OAG guide star options.

Denser star field targets in constellations in/near our galactic equator give more guide star options as well. Guiding quality was pretty much as expected and was directly related to how well I kept the main imaging train focused since deviations in the main scope of course end up making the OAG/PHD2 combo work harder to detect the star shifts in the guide camera if not within reasonable tolerances of course.

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Scott Badger

Nov 13, 2021 · Edited: Nov 13, 2021

Binning helped me as well with a 174MM and ZWO OAG plus Edge 9.25. As mentioned above, never at a complete loss of star selection, but sometimes no more than a couple that'll work and there have been times when the choice is either dimmer stars than I'd like or one that's saturated.

On a side note, I'm sometimes surprised at how dim the star is that PHD2 selects automatically when there are brighter non-saturated stars available..... It might hit the numbers, but more easily lost if there's any decline in transparency like any haze moving in or passing cloud.

And on that note, for those that try to get some sleep while imaging, has anyone set up a bedside alarm using PHD2? Seems like an excellent way to know if something's gone awry, like a snagged cable, or if clouds and maybe even rain is moving in. AP has made me much more aware of cloud formation (ha!), and I'm amazed at how quickly it can go from completely clear to totally overcast, literally in minutes.....like while I'm staring at the guiding graph to make sure everything is starting out ok and suddenly the guide star is gone and I start looking for a system problem only to finally look up at the 'clear' sky and see all white instead! Seems like going to bed while imaging is a bit of Russian roulette....no matter how good the forecast, some morning I'm going to wake to a very unhappy mount, cameras and laptop.....

Cheers,
Scott

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