Mirrors?

I would like to throw a question out to see what people think is the best primary mirror for our hobby. The reason I’m asking this is I currently have a 4-year-old 12.5” Discovery mirror. I’ve had some people look through my scope and could not believe how good the optics are. But I’m upgrading to a used 20” Obsession telescope that I’m getting from Dave Candela that has an OMI mirror. Yea, yea, I know you can’t compare the views in a 12.5” to a 20”. But you can talk about how good a mirror is in terms of its optics. So any opinions?

The OMI should be as good or better than the Discovery.

George Andrew said:

...... But I’m upgrading to a used 20” Obsession telescope ....that has an OMI mirror. Yea, yea, I know you can’t compare the views in a 12.5” to a 20”. But you can talk about how good a mirror is in terms of its optics. So any opinions?

I have an Obsession 20 (which I bought used) with an OMI mirror. It is excellent.

Ask the seller for the serial number of the mirror. OMI publishes on their website the test results for each mirror they produce by number, and that includes the mirror test images. Anyone who knows how can "test" the mirror based on those images. If nothing else, you can see if it has a turned edge.

George N

The scope was built in 2004, so I'll guess the mirror was made in 2003-4.

david goldman said:

in conclusion, i have yet to test a first rate "COMMERCIALY" made mirror for a simple reason, they do not exist!

Gotta disagree with you there.

No one has answered my question. I guess there would have to be an independent testing lab take a look at a random sampling of mirrors from several companies to come to a conclusion. And we know that’s not going to happen, Schrödinger's Cat in the bag.

I get it though; some commercial mirrors are good, some not so good, some handmade are good, some not so much. Since we can’t look through each other’s scopes or better yet I can’t look through your. How can you tell you have a good mirror or not, without testing it? I guess I should have asked; visually what makes a mirror good when you are looking at objects? Generally when I look into my scope, the 12.5, the stars are very crisp. I’ll put my 13 Ethos in and the stars that are in the outside of the field are crisp also. I’ll have diffracting spikes from the secondary from time to time depending on the EP. I’ve scene the Vail with out the OIII in an ok dark sky spot. In the same spot I’ve scene the California nebula with the H-Beta. I don’t have DSC’s so I say for sure but several weeks ago I think I saw some galaxies in Pegasus that were not NGC’s but PGC’s listed in Sky6. I know this sounds like I’m trying to say my 12.5” mirror is great, but the views speak for themselves.

Now here is your chance to boast about your scope. What mirror do you have, what size is it, and what have you scene? Maybe we can get somewhere with this question!