100mm vs 80mm, Worth? (1 Viewer)

G

Granpoli

Well-known member

• Feb 24, 2025

• #1

Hi,

Well, I have a question, for static bird watching, i.e. not having to carry the telescope on the tripod over the shoulder, but in a fixed position... would I need a 100mm instead of an 80mm?
Same brand, same lenses, maximum zoom 60x vs 67x..?
Can anyone advise me?
Thanks
Gpoli.

 

Mono

Hi!

Staff member

Supporter

• Feb 24, 2025

• #2

The biggest advantage wouldn't be the extra magnification but the extra brightness at lower magnifications.

Whether this is worth the extra cost is up to you. I don't know what brand you were considering but looking at the (recently discontinued) Opticron ES range the 80mm was £650, the 100mm was £1100, a big difference.

 

G

Granpoli

Well-known member

• Feb 24, 2025

• #3

Thanks,
This is the Regal M2 nodel.

 

W

wllmspd

Well-known member

• Feb 24, 2025

• #4

You always “need” more power, though as noted the brighter image is what is probably more valuable. I adjust the magnification so I get a “nice bright view” for the conditions, a bigger scope would enable this at a higher magnification. You could also look at astro “apo” refractors that might give more option, but are not sealed and are typically much heavier. Your wallet, observing sites and desire to lug a heavier scope are the determining factors. When I start to think about getting an 80mm, I remind myself how easy to carry about the 60mm is. Whatever scope you get, make sure you’ll be happy to get it out wherever you want to take it.

Peter

 

J

jring

Well-known member

• Feb 25, 2025

• #5

Hi,

for fixed observation, indeed a used 100-120mm astro ED doublet will be great... a cheap skywatcher or an expensive Tak fluorite doublet is up to you...

Joachim

 

Hermann

Well-known member

• Feb 25, 2025

• #6

jring said:

for fixed observation, indeed a used 100-120mm astro ED doublet will be great... a cheap skywatcher or an expensive Tak fluorite doublet is up to you...

Click to expand...

Doesn't Astro Physics make a decent 120mm scope?

Hermann

 

J

jring

Well-known member

• Feb 25, 2025

• #7

Hi,

I have only found 110 and 130mm triplets on the AP page... and the prices are certainly in the Tak triplet and quadruplet range... a Tak fluorite doublet is already kinda overkill for birding (although it certainly will be fine up to 200x or so on planets and whatever above 300x the double star crowd calls maximum useful magnification), using a fast imaging super apo is taking way over the top...

Joachim