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MM3/ MM4/ Celestron Regal m2? (1 Viewer)

hr21

Active member
Hi all,

I've narrowed my scope choice down to these three scopes.

I can pick up an mm3 with sdl v2 for £399 used

mm4 with sdl v2 for £549

or Regal m2 (65) with zoom (though I may change this) for £240, I would put a BST Explorer 15mm on it instead

I was wondering which one would be the best decision in the long run?

Thanks.
 
Hi,

that is an interesting question - first of all, are the MM3 and MM4 examples 50 or 60mm. The 50 ones are nice travel scopes but you probably will want a full size scope for longer distance views at some time.
The 60 or 65mm examples on the other hand might be all you need unless your usage profile has a large amount of seawatch etc.

In general with spotting scopes and especially when buying used - sample variation is present and it is a good idea if you can try the example you'll get in person.

Joachim
 
Hi,

while I am a big fan of the SDLv2 zoom (which performs admirably on my old Kowa TSN-3), I would actually try the Regal first... it's cheapest and largest and if it's good, you can get a nice wide angle fixed EP for it in your preferred magnification. A 15mm or 26x would be too low for my taste... I would aim for 9mm or so giving 40 something...

It is a bit heavier than the MM3/4 at 1.3kg vs 1kg though (both with zoom).

Joachim
 
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Hi,

while I am a big fan of the SDLv2 zoom (which performs admirably on my old Kowa TSN-3), I would actually try the Regal first... it's cheapest and largest and if it's good, you can get a nice wide angle fixed EP for it in your preferred magnification. A 15mm or 26x would be too low for my taste... I would aim for 9mm or so giving 40 something...

It is a bit heavier than the MM3/4 at 1.3kg vs 1kg though (both with zoom).

Joachim

Thanks.

I actually have this in hand currently.

It has the 15-45 zoom on it, pretty good until x32, after than softens up a fair bit. Could just be the eyepiece though.

Debating whether to hold onto it or not currently.
 
Hi,

hm, soft after 32x doesn't sound well, do you have a shorter astro EP at hand like 5 to 7mm? Then you could do a star test.

If not, do it with the zoom - usually EP aberrations are only visible in the field, so if the star is centered, you'll get ok results.

Joachim
 
Hi,

hm, soft after 32x doesn't sound well, do you have a shorter astro EP at hand like 5 to 7mm? Then you could do a star test.

If not, do it with the zoom - usually EP aberrations are only visible in the field, so if the star is centered, you'll get ok results.

Joachim

How do I do a star test?


Thanks.
 
Hi,

you aim the scope at a bright star, bring it to best focus and then bring it out of focus slightly in both directions. You should ideally see concentric circles which look the same inside and outside of focus.

See the images on http://www.telescope-optics.net/star_testing_telescope.htm for reference on what things look like - in your case the unobstructed images are relevant.

If the circles are not really round, but rather ellipses, whose main axis changes direction by 90 deg from inside to outside, your instrument has astigmatism (aka stig). If the circles are not concentric, there is coma. If the circles are fairly sharp on one side but "wooly" on the other, there is spherical aberration (aka SA).

Joachim
 
Thanks.

I actually have this in hand currently.

It has the 15-45 zoom on it, pretty good until x32, after than softens up a fair bit. Could just be the eyepiece though.

Debating whether to hold onto it or not currently.
Hi, I believe the Regal 65 has the same eyepiece as the 80 mm. My Regal 80 M2 is also soft but above 45-50x which corresponds well with yours being soft above 32x. I've therefore replaced the eyepiece with the Baader Hyperion zoom mark IV. And now it's sharp all the way and the picture is noticeable better overall compared to the original eyepiece. It's actually like I have gotten a new and much better scope. Even though I had read a lot of positive reviews of the Baader zoom eyepiece I could never expect the difference to be this great.
 
BST Explorer 15mm on it

that ep is nothing special. dunno what your budget is.....

https://www.ebay.com/itm/Vixen-1-25-SSW-Ultra-Wide-Eyepiece-14mm-37125/142249184995

https://www.ebay.com/itm/Baader-1-25-2-Morpheus-76-Wide-Field-Eyepiece-12-5mm-2954212/123135344251

a cheaper, classic...

Meade-15mm-Series-4000-QX-Wide-Angle-Eyepiece-1-25-034

Hi,

if the o.p. is looking for a fixed wide angle EP in the 25 to 30x range, then indeed some astro EPs might come in handy - 15mm yields 25x, 12.5 = 31x.

The Baader Morpheus 12.5 is warmly recommended and fully compatible with any kind of glasses. The Vixen isn't and quite franky is a bit expensive - the Morpheus 14mm will probably a better deal.

For something really cheap and a bit higher mag (35x) and wider field (82 deg afov - but not really compatible with glasses at 13mm ER and probably a bit less useable ER), the 11mm Explore Scientific is an awesome deal at 160$ (or less if you find it used or on sale).
The others from this series are too - just avoid the 14mm which is not so great with fast instruments due to showing field curvature in fast instruments like a spotter.

A little caveat though - as with all astro EPs in spotters with their quite limited focus range - there is no guarantee that you will come to focus at infinity or even terrestially, so try before you buy or get them at a shop with a good return policy...

Joachim
 
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