Looking for a new telescope, possibly 4" refractor.

[Totnesdave]

Hi there, just joined the forums, was pointed here by Martin at FLO

As mentioned in the 'welcome' post I'm looking at getting a new telescope, to replace my old and defunct refractor.

I'm all ears for advice, as browsing the internet has put my head in a bit of a spin, especially with the breadth of new equipment available compared to when i was last involved.

I have seen a couple of options which have caught my eye, but I'll lay out my expectations and situation first so as to try and focus on my needs, so to speak.

My favourite targets are the planets and moons and I want to get some more useful extra clarity and power over my old 2.4" refractor. I do enjoy searching for nebulae, star clusters also, the challenge of patiently hunting an elusive object. Lunar observation is enjoyable too, especially when conditions don't allow much else. I also like to do some solar projection in the daytime to take a look at sun spots, flares.

I'm primarily into visual observation. I do have a digital camera, a Panasonic Lumic DMC FZ18 which it would be interesting to see if it has potential for digiscoping, with the addition of an RA drive.

I have only really experienced refractors up to now, I'm unfamiliar with reflectors, not sure how often their mirrors need re-silvering, realigning, is this a great issue ? SCT scopes look attractive due to their portability but also seem very expensive.

Portability wise, well, I have a limited viewing spot from my back garden, but there are dark spots in the countryside around me. My car is a Volkswagon Polo hatchback so with limited room with the seats down. Weight-wise, well what I've looked at seems to weigh in at about 40-50 pounds, or in my terms, a Fender Blues Deluxe valve combo amplifier, which I can heft with no problem and also contains fragile glass

The two scopes which *have* caught my eye are the Celestron C100-ED on a the CG-5 mount, and the Celestron Omni XLT 120 on the CG-4 mount, which both appear to match my instinctive wish for a larger and better quality refractor on an equatorial mount, and both can be retrofitted with motor drives at a later date. I don't think I'm too fussed about GOTO, I enjoy locating things myself, the thrill of the hunt

Now as far as those two scopes are concerned, from extensive googling it seems the C100 is better mounted and with better glass (for reducing chromatic aberration) and is currently the subject of many closeout deals (why I wonder ?) while the XLT 120 has a 'less robust' mount, although the C100 does appear to have some tricky clamshell ring arrangement which sounds suspicious. Both fall into the possible budgetary range of "about £400 pounds or so".

So, I'm keen on advice on the relative merits of those two telescopes, and the CG-4 vs. the CG-5 mount etc, but ... without wanting to pre-bias the request for advice to much : given what I've said above about what I enjoy and what budget I have, and also that this will (probably) be my only telescope……. what is 'out there' that people more in the know might think matches my needs ? I've probably overlooked a lot of equipment in pure ignorance

Thanks for any advice anyone can give, I seem to have rambled on a lot, as ever

cheers

Dave.

[GazOC]

Hi Dave,

Welcome to SGL.

Although they are both fine scopes I'd go with the C100. You are sacrificing a little aperture over the Onmi but I think the sturdier mount and reduced chromatic aberration makes for a better visual setup.

As far as I'm aware theres nothing "sinister" about the C100 being on sale other than its an "end of line" item which is not really a problem as you are not likely to need any "spares" for it.

Another scope you might want to take a look at and get opinions on is the 127mm SkyMax MaK/Cass. Its a very good lunar/ planetary scope in its price range and very compact.

HTHs

Gaz

[F15Rules]

Hi Dave, and welcome.

I have a C100ED available and have sent you a pm about it. A truly superb scope for the price.

cheers

Dave:)

[F15Rules]

:pHi Dave,

Me again..I meant to say, I also love guitars..my avatar picture below is my Marlique Reborn Series Broken Wings - rare in this country and based on a Yamaha SG shape, with coil tapped humbuckers, sounds better than a Les Paul!

My other guitar is a Fender Japan Strat '57 reissue in cherry sunburst, lovely axe with great sounds across the spectrum.

I only play at home these days, and put them through a nice old 70s Marshall 30 Watt Solid State Master combo with Celestion speakers and overdrive channel...

Now the astro only boys and gals are really confused!!

What gear do you play?

Dave

[Moonshane]

I have the OMNI 120 and love it. that said, I have added a 10:1 dual speed focuser and also changed the mount for a Vixen GP and made my own tripod. http://stargazerslounge.com/diy-astronomer/99448-home-made-wooden-tripod-refractor.html

one of the reasons was that I sold the CG4 and tripod along with an OTA 150 OMNI reflector. I always found it quite a stable set up and the gearing is lovely and smooth.

there's not a lot of aberration with my OMNI, being quite a long tube - f8.3. it is sometimes there but not really a problem. the main reason I wanted to change the tripod was that the CG4 tripod is quite low especially when looking at the zenith or nearly so. I think the CG5 tripod is a little taller and also 2" rather than 1.75" tubular legs?

I have never looked through an ED scope but assume it's not just that they have less chromatic aberration? I'd be interested to hear opinions too about what makes ED scopes so much better compared with eg a longer achro - as I also might eventually get one - I'd always buy used myself - much better deals as long as you buy from someone decent - i.e. from this forum!

with the above reservations (i.e. mainly never having looked through an ED scope) I'd definitely recommend the OMNI 120.

[Totnesdave]

Heh thanks for the guitar info Dave Just to confuse people further, I mainly use an 1996 USA Fender 'Buddy Guy' Stratocaster, also recently picked up the 1989 G&L ASAT in my profile pic, got a 1989 Les Paul, and a number of other guitars which I play through a bunch of old analogue effects and a couple of Fender tweed valve Blues Deluxe and Junior combos. I'm a traditionalist, you may have guessed !

Oh yes, got a Brian May 'Red Special' lurking in my guitar cupboard too and the orchestral harmoniser pedal to go with it hee hee Met Brian along with Patrick at a recent book signing in Paignton for 'Bang', two wonderful chaps

Back to topic !!! ….

Mmmmm still oscillating between those two refractors right now, and tempted by Dave's pm too !

Dave

[Totnesdave]

Mmmm what are the relative merits of a 4" refractor and say the Skywatcher Skymax 127 5" Maksutov Cassegrain :

Maksutov - Skywatcher Skymax 127 (EQ3-2)

I am in utter ignorance of Cassegrain scopes, but it does appear more 'grab n go' - how is it for planetary observation though ?

Dave.

[John]

The Maksutov-Cassegrain is an excellent design for planetary observation, having a long focal ratio and a relatively small central obstruction. 2 issues that you would need to take into account in comparing a Mak with a refractor are that the cool down time of the tube / optics of the Mak will be longer than a refractor and the Mak will need a dew shield as an "extra" as the corrector lens at the front of the tube has a tendancy to dew up.

The ultimate performance of a good 4" refractor and a 5" Mak will be quite close but under good observing conditions the Mak's additional aperture should reveal a little more contrast and detail. The Mak design is colour-free of course but then so is the ED100, virtually.

[cootuk]

Having bought Dave's Towa I can say you would get a well looked after bit of kit.

That Tal also looks tasty.

[robhal9000]

Hi,

As you are an relatively experienced observer you may want to consider one of the small dobs which represent excellent value for money.. Downside is collimation, lower focal length (less forgiving of cheaper EPs) and cooldown time. Not major issues. Not quite as portable as a 127 but not too big for the car. A SW 150mm dob is about £180.

A SW Skymax 127 with tracking would be my choice below 300 quid. You don't have to keep bumping the scope to keep things in the FoV. The second hand 5se in the for sale section is good value for less than 300 and with GOTO.

[Totnesdave]

Thanks for the advice on this thread guys

After a lot of thought and background reading, I think I'm going to go with the Celestron C100ED on a CG-5 mount, the current crop of clearance deals available put this bang on my £400 budget and I like the fact it appears to have a sturdier mount and more colour free ED optics than the Omni XLT 120 achro at a similar price point, even if sacrificing aperture.

A little down the line, I'd like to equip the mount with tracking drives ... is there a recommended set for this available, I couldn't find a definitive recommendation ( Celestron's seems to be discontinued: link here ) but I have seen it suggested that the Skywatcher EG5 drive set will also work ?

Found a nice observing site I think, a nearby arboretum park on a steep hill, just over the road from where I live, as my back garden has tight limitations, looking forward to getting up there under clear skies

cheers !

Dave.

[nicnac]

the CG5 is better than the EQ5 in my opinion, the EQ head is practicaly the same but the CG5 has 2" steel tripod legs making things much sturdier

[ollypenrice]

I think the close out deals on the ED100 variants will be to do with its slow focal ratio. It is really too slow for deep sky imaging. I think we can expect a faster 4 inch from China. However, that r-ratio is a positive benefit for your purposes on the moon and planets. It will give a better image scale and colour correction. There should be a lot you can see with it. I remember in the UK once catching a shadow transit on Jupiter from beneath a sodium street light in a 4 inch refractor...

Olly