Doublet vs. Triplet

[jkdnys]

Just a quick question, I was at the local telescope shop (CCTS in patchogue, ny is excellent btw) and the owner highly recommended a triplet for astrophotography. But I was online and it looks like I can get a little more telescope if I go with a doublet (both are ES models). My question is, for a beginner, which type would be the best bang for my buck. The two I'm looking at are the ED 80 vs. the AR152

Thanks

[Leveye]

You'll get less chromatic aberration from a triplet. My Stellarvue SV80ED doublet gets some purple fringing but it is easily removed in post.You can also use a fringe killer filter. I don't find a triplet to be any sharper than my doublet in the lower end models. I've owned them both and went with the less expensive doublet. I'm very happy with the pictures.

[nmoushon]

If im not mistaken isnt the AR153 an Achro? If so then that is going to add some chromatic aberration that is not wanted. 

Now you can get an Apo doublet that is much better at correcting the CA than the Achro. The triplet Apo does a better job at it but if your on a budget then I wouldnt bother with the triplet. My scope in my sig is an ED80 doublet Apo and I havent had any problems with my it. Though with a doublet you wont be able to reduce it as much as you would a triplet because the CA will start to really show up. If you keep at around F/5 or slower then you shouldnt havent to worry. For a beginner I would suggest an Apo doublet, not the Achro, so you dont have to spend as much to make sure you really want to get into this hobby more seriously. 

[lensman57]

Just a quick question, I was at the local telescope shop (CCTS in patchogue, ny is excellent btw) and the owner highly recommended a triplet for astrophotography. But I was online and it looks like I can get a little more telescope if I go with a doublet (both are ES models). My question is, for a beginner, which type would be the best bang for my buck. The two I'm looking at are the ED 80 vs. the AR152

Thanks

Hi,

AR 152 is an achromat, these have poor correction ( in the blue region in particular ) and are not suitable for serious AP due to excessive fringing and other aberrations. By ED 80 I guess that you mean an SW ED 80 F7.5, if so then this scope is extremely well corrected for a doublet and aan optical bargain. A bit on the slow side but with a sensitive camera more than capable of producing great results. The focuser adequate. As for other EDs from other makes you have to do a bit of research or ask around. A good triplet will outperform a good doublet but at a price.

A.G