Just a few QUESTIONS!

[lw24]

Hi, I've got a few questions that I was hoping you could answer.

1) I'm going to buy a Skywatcher Startravel 120 on an AZ3 mount, however I see alot of people slamming it saying that the ST102 and ST80 are better telescopes, how? The ST120 has more aperture and therefore better detail.

2) Why do people praise the ST80 so highly, have I missed something? And if it's so good, could I mount it onto the AZ3 mount I get with my ST120 at a later date?

3) Would I be able to mount a Maksutov Cassegrain (e.g Skymax 90T OTA) onto the AZ3 mount? (I was thinking of getting a refractor for wide field views of DSO and then get a Maksutov for planetary viewing).

4) Whats the best way of preventing Chromatic Abberation? I've heard a moon filter does the trick on the moon, but for Jupiter/Saturn what would be the best (Orion -V filter, Baader Semi Apo, Baader Minus Violet)?

Cheers!

[lw24]

Anyone? I need some questions answered!

[zcapp96]

There is NO magic filter that prevents CA and on the scope you discribe it will be Very evident. If there was such a filter why would takahashi sell any APO's for several thousand pound if everyone could just spend a few pound on a filter!

The ST80 is praised so highly for it's use as a guide scope, not as a visual telescope.

[John]

The best way to prevent CA is to avoid fast achromatic refractors !. But they are nice for wide field, low to medium power deep sky viewing.

I feel that the AZ-3 might be slightly over it's limit with the ST120. An AZ-4 would be a much steadier mount for that optical tube. The AZ-3 is fine for the ST80, ST102 and 90mm Mak-cass though.

Your idea of having two scopes with different purposes in mind is a good one I think. Scope designs that do everything well are fairly uncommon.

[lw24]

Hmm, I'm now considering the Skymax 90/102, but have a few questions about it.

Are either of these (90/102) more portable (on the EQ2 mount) than the Skywatcher ST120 on an AZ3 mount?

Approximately, how long does it take for each one (90/102) to adjust to the temperature? (temperature stablisation?)

How good are they for viewing Deep Sky Objects (Messiers) as I am concerned about the long focal length and therefore the large f ratio (about f/12)?

Could I buy an eyepiece to make the FOV much bigger in order to view some DSO? If so, what one?

Do the 90/102 need collimation or any service?

Cheers, I hope you can help!

[themos]

It seems you want to know what "the best" is, down to all conceivable angles, but you are asking for detailed information which you expect to be given for free. Is anyone else getting annoyed?

[lw24]

So you're saying that me, as an beginner to astronomy shouldn't be able to recieve free information. I'm just trying to find out what telescope is best for me, thats all...

[swamp thing]

It seems you want to know what "the best" is, down to all conceivable angles, but you are asking for detailed information which you expect to be given for free. Is anyone else getting annoyed?

If your getting annoyed may i suggest that you don't read the thread

I think this section is titled Equipment HELP after all.

Regards Steve

[John]

Here's my take on your questions:

Are either of these (90/102) more portable (on the EQ2 mount) than the Skywatcher ST120 on an AZ3 mount? - No. IMHO the AZ-3 is more portable, but not with the ST120 on it.

Approximately, how long does it take for each one (90/102) to adjust to the temperature? (temperature stablisation?) 30-60 mins. Depends on the temp adjustment needed of course.

How good are they for viewing Deep Sky Objects (Messiers) as I am concerned about the long focal length and therefore the large f ratio (about f/12)?. OK but they are smallish aperture scopes with narrow fields of view.

Could I buy an eyepiece to make the FOV much bigger in order to view some DSO? If so, what one?. 32mm plossl - max FoV with a 1.25" size. 2" won't work with the small maks.

Do the 90/102 need collimation or any service? No, not really, unless you drop or kick one !.

Be sure to give me marks out of 10 compared to the responses you get over on "Cloudynights"

[zcapp96]

You are perfectly entitled to ask for help! I must admit that I am a little concerned as to what you expect to see through the telescope. You seem to want to see DSO's the most but for these you really need as big a scope a possible. Most will appear as a grey smudge in anything under a 6-8" scope. Before you part with any cash try to go to a society met up and look through other people's scopes, even if it means a bit of a journey. Will give you a much better idea in the long run.

[JAO]

Iw24

You obviously are intested in DSOs. Have you considered a dobsonian. You will get more aperture per pound and learn your way around the sky in the meantime. Dobs alo give reasonbale planetary views at low to medium powers.

It might be worth rethinking your choice of scope based upon what you might do most out in the field.

It is a challenge selecting a scope and we have all been there. All scopes are a compromise between cost, the function you want them to perform, issues like storage and transport and of course the location from which you observe. Keep asking questions. I really agree with zcapp about trying to get a to a local club to get a chance to try a few scopes before you buy. It could save you a lot of time and money in the long run.

Adrian

[ItIsOnlyMe]

Is anyone else getting annoyed?

Nope...

It is always difficult to know what question to ask and how to ask it.

Which is why these forums are a great place for beginners and the less knowledgeable, like myself, who are invariably met with a great deal of patience and "free" advice, much of which would be well worth paying for.

[dark star]

I have a skywatcher 120 st refractor which is really good. The AZ3 mount is usable, and I have used it for a couple of years, but if you have the money get a AZ4 as this will be even better. The AZ3 mount is not perfect and not quite strong enough for the weight of the telescope, but I have in any case got a lot of fun out of it.

After a while you may want a bigger telescope which will show you more things, and I would recommend a 150mm dobsonian or reflector.

I quite happily have both! The 120mm refractor is great for wide views, but if I had to choose one telescope I would choose the 150mm dobsonian or reflector as it will help you to see more. For example, I saw the Ring Nebula through my Skywatcher 150pl reflector for the first time. With bad light pollution I could not see it with the refractor.

Another possibility is 100mm binoculars, they will give great widefield views like the refractor, the disadvantage is that you have much less magnification than with a telescope.

The Skywatcher 120 st refractor is really terrible on planets, as there is a lot of false colour because of the telescope's optical design, a longer focal length refractor gives better views, but is much more awkward to mount and use, and a refractor that is corrected optically to solve this problem (an apochromat) is rather expensive. On the other hand, if you use it for looking at star r clusters etc. the Skywatcher 120 st refractor is excellent.

[lw24]

You are perfectly entitled to ask for help!

Quote:

Originally Posted by themos

Is anyone else getting annoyed?

Nope...

It is always difficult to know what question to ask and how to ask it.

Cheers guys, I'm glad you appreciate the situation I'm in right now, I just want to find out what the best telescope for me is.

I'm sorry buy a Dobsonian/Reflector wouldn't be practicle for me in terms of portability and space, thanks for the suggestions though.

You say the ST120 isn't portable on an AZ3, so would you reccommend getting the ST102 on the AZ3, so I can spend a little extra cash on accessories?

[lw24]

I have a skywatcher 120 st refractor which is really good. The AZ3 mount is usable, and I have used it for a couple of years, but if you have the money get a AZ4 as this will be even better. The AZ3 mount is not perfect and not quite strong enough for the weight of the telescope, but I have in any case got a lot of fun out of it.

The Skywatcher 120 st refractor is really terrible on planets, as there is a lot of false colour because of the telescope's optical design, a longer focal length refractor gives better views, but is much more awkward to mount and use, and a refractor that is corrected optically to solve this problem (an apochromat) is rather expensive. On the other hand, if you use it for looking at star r clusters etc. the Skywatcher 120 st refractor is excellent.

I can't really afford an AZ4 mount at the moment, but could possibly upgrade in the future.

I understand the problems to do with Chromatic Abberation. I'm not really buying this telescope to be good with planets, more star clusters and the occasional nebulae/galaxy, however a nice view of the moon would be nice.

I've heard that a moon filter can help to reduce the CA on the moon, so I might try one of those.

____________________________________________________

I was looking at the Skywatcher Skymax 102 on the EQ2 mount, how portable is the EQ2 mount?

Cheers

[NickK]

I was looking at the Skywatcher Skymax 102 on the EQ2 mount, how portable is the EQ2 mount?

Looking at the EQ2 on the SW site here it appears the mount weighs:

Counterweight(s) 2.08kg

Tripod Weight 12.5kg

Although a mount and tripod are two separate things usually! The Vixen Porta II mount is 6.8 Kg including tripod (although not Equatorial and probably less stable due to it being lighter).

I have the smaller Porta I mount and a Vixen A80Mf and together I can pick the thing up at full arm's reach! Probably about 10Kg in total!

The problem with a grab and go is that, if you do wish to go higher mag (x151) then it will wobble with touches without the bendy adjustment knobs.

[lw24]

A tad bit too expensive for my liking.

I'm probably going to go for the Startravel 120 on the AZ3 mount.

I've heard it's a bit lens end heavy, but apparently mounting the tube further up helps to resolve this issue.

Cheers for the advice, it's been a great help!

[dark star]

I think you will enjoy the 120 ST refractor and AZ3 mount, I have had a great time with them. It is very portable as regards moving it from house to garden, around a garden or transporting in a car, but is rather heavy to carry with the mount any distance, although I have carried them for around 15 minutes to a place near home which is a bit darker (using a very big rucksack for the telescope and carrying the mount) !

[NickK]

I have carried them for around 15 minutes to a place near home which is a bit darker (using a very big rucksack for the telescope and carrying the mount) !

Hehe with an EQ6 that's about 15 feet not minutes carrying!

[great_bear]

Is anyone else getting annoyed?

To be fair - It's very scary blowing a huge wad of cash on a telescope and when you're only 14 years old, you're bound to have a lot of questions.

[SiriusB]

The best way to prevent CA is to avoid fast achromatic refractors !

LOL! 1-0 to the reflectors.

It seems you want to know what "the best" is, down to all conceivable angles.....

Seems like a wise philosophy to me:- if i'd thought longer & asked more questions i might have got my equipment choice right 1st time round instead of 99th time.....& saved a few £in the process.

....

I'm probably going to go for the Startravel 120 on the AZ3 mount.

I've heard it's a bit lens end heavy, but apparently mounting the tube further up helps to resolve this issue.

Actually on the az3 mount a lens end heavy scope is to your advantage, due to the way the balance of the mount works, or more correctly doesn't work!

Well here's a few thoughts:

I own a st120/ az3. Chosen because its the largest, lightest package i can transport in a large rucksack.

You will struggle to find a lighter mount with equal or better stability IMO. It can be improved with a bit of diy, a web search for az3 mods should turn up some ideas, including some featured on SGL.

I too feel the st120 is a little heavy for the mount, an st102 would be better matched,but don't be put off.

It's hard to know what you as a beginner are expecting to see through a scope.

Most dso enthusiasts go for 8" plus scopes,&with good reason. I'm personally happy with the 4-5" views, but you will need access to reasonably dark skies to avoid major disappointment.

Comparing the st120 to a mak 127, the st performs better on dso's, indeed my calcs suggest it's equivalent to a 95mm ish "perfect" refractor on light grasp.Still enjoy the mak on dso's though,nice scope.

The field of view on the 90/102/127 mak is enough to show most dso's, the difference with an ST is the wider field of view makes finding the objects that much easier in the first place.

You can indeed put a mak90 etc on an az3 mount, but will most likely need the "az3 camera mount adapter plate" Think FLO sells it.

For portability i think the ST range & Maks complement each other nicely.

Don't rule out a 5 or 6" reflector, probably a bit bulky on an equatorial mount for easy portability, but a possibility on an az3?

Anyone out there tried it??

Err, hope all that helps....

[John]

....Don't rule out a 5 or 6" reflector, probably a bit bulky on an equatorial mount for easy portability, but a possibility on an az3?

Anyone out there tried it??...

Not a newtonian but I have used a 5" Celestron schmidt-cassegrain on an AZ-3 and it was pretty good - nice short tube, which is what the AZ-3 prefers

[lw24]

Cheers,

you will need access to reasonably dark skies to avoid major disappointment

I'm not expecting to see DSO from the middle of town, I plan to drive out somewhere where I think there will be dark skies (the reason for getting a fairly portable refractor).

My order of purchases should be like this:

Skywatcher Startravel 120 (AZ3)

Moon Filter

Baader Semi Apo/Fringe Killer

Skywatcher Skymax 102 (OTA)

AZ3 Camera Mount Adapter Plate

I intend to have the first 3 purchases by a few months, and the Skymax 102 by a year - 2 years.

Thanks for the advice!

[John]

Cheers,

I'm not expecting to see DSO from the middle of town, I plan to drive out somewhere where I think there will be dark skies (the reason for getting a fairly portable refractor).

My order of purchases should be like this:

Skywatcher Startravel 120 (AZ3)

Moon Filter

Baader Semi Apo/Fringe Killer

Skywatcher Skymax 102 (OTA)

AZ3 Camera Mount Adapter Plate

I intend to have the first 3 purchases by a few months, and the Skymax 102 by a year - 2 years.

Thanks for the advice!

Are you planning on using 2" accessories now or in the future ?.

If so, remember that you will need 2" filters instead of 1.25" ones.

It would be a shame not to exploit the widefield capabilities of the scope to it's maximum !.

[lw24]

If so, remember that you will need 2" filters instead of 1.25" ones.

This was one of the things I was going to check. Annoyingly, it seems that 2 inch eyepieces/filters cost TWICE AS MUCH!!!

Surely I don't need a 2 inch filter for looking at the moon, it's not exactly like you need widefield capabilities too see it...