Scope Comparisons...

[Keiran]

Hi all,

I just want to gain more knowledge really, and maybe it will help me come up with a wish list for furture purchase. I am looking for reviews for both visual and imaging.

First off is Semi APOs...

-WO Megrez 72

-Borg 77EDII

-Televue 76

-TAK fs 60

I have had amazing views from my M72, could i expect a HUGH difference between these other scopes... Are they worth the extra cash. I know they are different apetures, focal lengths and different glass, but are they that different. What are you paying for, the glass, the name???

Next one is a comparison between the Apo Triplets...

Which ones have you tried, and that are they like compaired to others? I would be looking at about 5" and above.

Thanks for any help you can give

Keiran

[shaunster]

Keiran, of the scopes mentioned for visual I doubt you will notice any difference at all, aperture aside that is...

For imaging generally the more expensive ones will have better control of the blue channel and certainly a flatter field than the megrez, of course the Borg certainly is much faster than the others mentioned and still has amazing performance

The Borg is rated very highly and gets fantastic reviews, this would be my choice out of the scopes you have mentioned. The TV76 is way overpriced for what it is IMO... but im sure others will disagree

[Keiran]

Cheers for the response shaun... From what i saw, there is a hugh price difference between these scopes, can it be justified with the results you get?

Ill have to pop round one day to let you use the M72 and see what results you get compared to the ZS70 you have.

What about larger APOs?

And what scope would you recommend... What would you buy, and assume we dont have £6000 to spend on a scope ... Affordable but but good.

[ollypenrice]

Of the small ones for imaging I'd go for the Borg. I agree the TV is expensive but you have to bear in mind that it is built to last several lifetimes. I'm a Tak fan but not impressed by the FS60 for imaging. Poor control of the blue channel and too expensive by far. Nadeem has recently posted an image from the Megrez. I have a ZS66 which is not bad but the focuser is on the light side.

Of the bigger refractors I have imaged with the Meade 127, the expensive TEC140 and the Altair Astro 115. The TEC is the best, not surprisingly, though the flat field is larger in the Meade and much larger in the Altair 115 with its built in flattener. (A TEC flattener breezes in at 750 dollars...)

The Altair 115 has two rotators, built in flattener and gives a quite exceptional star test right across the field.

The Meade 127 does not control blue stars all that well but is otherwise good, but the 115 beats it on all counts in my view.

I have never tried the ED120 but wise voices on here rate it highly.

Just a thought on short FL options; for five hundred pounds I bought a Canon EF200L camera lens second hand from London Camera Exchange. This is optically better than any budget doublet I've imaged with once a fine focus device was added because at the fast f ratio the focal depth is measured in microns. I'm imaging the Antares region at the moment and it has controlled that star better than the FSQ, though it gives diffraction effects from the stopping down.

I also bought a TV Pronto on here for about 200 pounds and with a TV reducer flattener that might well see off the modern budget doublets. I have some winter projects lined up so may find out later... At least the fouser won't be an issue!

Olly

[Keiran]

Thanks very much for that Olly... There is alot of food for thought in that.

I dont think i am going to buy another small apo, as im rather happy with the M72.

I do notice that people are having problems with the M72 and the blue channel, but as im using a DSLR, I dont seem to have them problems.

... I havnt touched CCD imaging yet, that will come when i buy a house in the next year or so. When i have a perminant setup, i will invest in a CCD and larger refractor... and looking at that Altair 115 it would be in my price range.

One more question, What about flourite glass? How much difference does that make?? And what is the difference between FPL 51 and 53... I know one is better quality, but how much difference does it make?

[ollypenrice]

I'm not well informed about glass I'm afraid. Fluorite used to be the hallmark of the best refractors but seems no longer to be necessary. Takahashi no longer use it in the FSQs and yet have slightly improved the colour correction. However, I note that they continue to include the magic letter F (it is for Flatfield) but I think the marketing men proably wanted to keep it in there!

Neither of my premium apos uses Fluorite.

Olly

[Psychobilly]

Glass type and "APO" discussion.. that's CN territory if you have a few months of free time ... IIRC there was quite a long (in SGL terms) thread on here a few years ago...

[ollypenrice]

You are right, Peter. I'd always rather try a scope than read the spec!

I do wonder if the filter makers might be able to provide a dedicated blue filter which gave the budget apos a helping hand?

Olly

[Keiran]

Well thanks for the help then guys

Its amazing they havnt come up with anything to sort that out yet... what is it caused by??

[Psychobilly]

Here you go... the SGL version....

http://stargazerslounge.com/equipment-discussion/68403-fpl-53-fluorite.html

[Keiran]

Thanks Peter ill have a read through that...

[cs1cjc]

The place to look if you want actual measurements on scopes is:

Google Translate