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Ultra-portable kit list - Will this work?? Advice needed please!


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My first post! Hello all! ;)

I've just completed my 'foundations of astronomy' module on my planetary science degree course, and I'm about to take the plunge on some gear.

My primary requirement is that the kit is ULTRA-portable... I need to be able to fit it into my (already overcrowded) carry-on luggage for budget flights, as I plan to have nomadic country hopping existence for the coming few years.

The next important factor is that I'm on a very limited, student budget!

I have done a fair amount of research and am ready to make a purchase today, but I am hoping to get a little advice to hone my plan:

Scope wise, I'm pretty much decided on the Celestron C70 mini maksutov:

http://www.sglhost.com/budgetastronomy/welcome-to-budget-astronomy/telescope-reviews/maksutov-telescopes/celestron-c70-mini-mak/

Just £75!!!

Aperture: 70mm
Focal Length: 750mm (Physical length 280mm)
Mount Type: Table Tope Alt-Azimuth
Focusser EP Size: Custom (but 1.25″ adapter supplied)
Eyepieces: Zoom (25x-75x)

... It seems like phenomenal specs for something that is shorter than a school ruler!

Then, I'm planning to get replacement EPs... I'm currently leaning towards both the Vixen NPL 10mm & 15mm

And then using a 2x barlow... I am *utterly flummoxed* here... I struggle to differentiate between the following sub £40 options:

- Meade #126 2x

- GSO 2x (and 1.5x)

- Orion Barlow Shorty 2x

- Skywatcher 2x Deluxe Achromatic

............. From reading the forum chatter, I am getting the impression that the Orion might be superior... Whereas the GSO has the nice feature of interchangable 1.5x or 2x (though the usefulness of this is mitigated if I do indeed go for 10mm and 15mm EPs as there will be much replication of potential magnifications).

I figure that, with the combo of a 2x barlow and 10mm & 15mm EP (given the 750mm focal length of the scope) I will have the following potential magnifications:

50x

75x

100x

150x

... That maximum one just marginally exceeding the max practical magnification limit rule (70mm aperture x 2 = 140x).

>>>

My questions at this point are manifold:

1.) Is this kit list workable/compatible/functional... Or have I made some horrendous noobie oversights in the potential of this relatively small telescope's potential?

2.) Which of those barlows would you recommend the most for my situation? Are there any others in that kind of price range that I should consider (FYI, Tal are no longer available)?

3.) (Particularly given the limited light capturing potential of this small scope...) Am I being reckless to try to jack things up to 150x magnification? 

Is my jump from 100x to 150x a glaring hole, and I'd be better off switching EP choice to come in at ~130/140x?

4.) Am I right in thinking that- given the relatively small aperture- a moon filter will be completely unnecissary? Should I be looking at any other filters for this starter set up?

5.) Any other thoughts? Any other kit I should consider (either in addition to the above, or completely instead of the above)?

Many, many thanks for any advice!!!!

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PS, the Vixen NPL lenses are ~£35 each.

So the cost breaks down as:

Telescope £75

EPs £70

Barlow £40

Total = £185

... Does it seem odd to be spending such a small percentage of the investment on the scope itself?

Are there any other ultra portable options that might be better, for below £200?

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1. I think that will be quite a frustrating set up to use. I think those table top tripods are pretty hopeless, but happy to be corrected. For mounting it, you will find a lot more choice in photography tripods.

2. I think the Orion and GSO barlows will probably be decent

3. You will perhaps achieve 120x magnification, but not a lot more. That central obstruction kills the resolution quite a lot.

4. Don't bother with a moon filter. I don't even with a 12" scope. The only filter I might think about is a UHC filter, but it's not really worthwhile for this scope.

5. To be quite honest, I think you will find a pair of 15x70 binoculars with a mounting solution of one kind or another far more enjoyable to use, not to mention more portable and probably cheaper. The wider fields of view are much more enjoyable with this aperture.

As for your question in your follow-up, it's very common to have the scope as a relatively small proportion of the total set-up.

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Hi and welcome to SGL, Interesting question you have there i dont know this MAK or its long term reliability regarding colimation etc but it does look ok. It might be worth considering binoculars or an actual spotting scope with a zoom eypiece too.

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Thanks for the welcome and the swift replies- great to find such an active forum!

1. I think that will be quite a frustrating set up to use. I think those table top tripods are pretty hopeless, but happy to be corrected. For mounting it, you will find a lot more choice in photography tripods.

2. I think the Orion and GSO barlows will probably be decent

3. You will perhaps achieve 120x magnification, but not a lot more. That central obstruction kills the resolution quite a lot.

4. Don't bother with a moon filter. I don't even with a 12" scope. The only filter I might think about is a UHC filter, but it's not really worthwhile for this scope.

5. To be quite honest, I think you will find a pair of 15x70 binoculars with a mounting solution of one kind or another far more enjoyable to use, not to mention more portable and probably cheaper. The wider fields of view are much more enjoyable with this aperture.

As for your question in your follow-up, it's very common to have the scope as a relatively small proportion of the total set-up.

1.) Yes, the tripod does look flimsy, but (as you note) it can always be replaced with a standard camera one.

2.) That's good news... The GSO Barlow is the one with the 2x AND 1.5x amplification.

3.) .... So in that case, maybe I could just get a single 12mm EP + the GSO... Which would give me the following potential magnifications-

62.5x

93.75x

125x

4.) Thanks- I'll skip the filters for now then.

5.) I did briefly consider binoculars, but it ostensibly seemed a waste of my precious space to take two identical optical chambers in parallel... My thinking was it would be better just to get a better quality single barrel (sorry for terminology!!) and max out the quality of that one.

New questions then-

Am I flawed in this thinking about binoculars?... I can't really see much advantage of them, other than their durability/ease of use (??)

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Hi and welcome to SGL, Interesting question you have there i dont know this MAK or its long term reliability regarding colimation etc but it does look ok. It might be worth considering binoculars or an actual spotting scope with a zoom eypiece too.

Thanks.

'an actual spotting scope'... Ca  you please clarify this- I thought the C70 is a spotting scope? Can you recommend any examples of what you mean?

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You need a red dot finder and some means of sticking on the tyube.

Ihave this mak and the fov is very narrow.

You will need to either always leave an eyerpeice in or need a bung for the eye hole to keep the tube clean when not in use.

Thanks for the tip on the bung. Useful to know.

... I'm as green as they come... Please can someone provide a link with an explanation about what red-dot finders do? I tried to Google the info, but found supprisingly little in the way of explainations!

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Thanks.

'an actual spotting scope'... Ca  you please clarify this- I thought the C70 is a spotting scope? Can you recommend any examples of what you mean?

The C70 is a spotting scope but is also a MAK that tends to put it into the "telescope" bracket, I dont have any recomendations for actual spotting scopes but these are a couple of examples.

http://www.firstlightoptics.com/celestron-spotting-scopes/celestron-ultima-80-angled.html

http://www.firstlightoptics.com/acuter-spotting-scopes/acuter-spotting-scopes.html

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A Red Dot Finder is a zero magnification pointing tool that uses a coated glass window to superimpose the image of a small red dot onto the night sky. Once you align this with your scope it allows you to find the thing you're trying to look at. Some (more expensive) options project rings of known diameter, rather than a dot; this is useful in star-hopping.

Edit: And if wanting low cost and really portable, I'd consider binoculars and a tripod of some sort, as mentioned above.

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The C70 is a spotting scope but is also a MAK that tends to put it into the "telescope" bracket, I dont have any recomendations for actual spotting scopes but these are a couple of examples.

http://www.firstlightoptics.com/celestron-spotting-scopes/celestron-ultima-80-angled.html

http://www.firstlightoptics.com/acuter-spotting-scopes/acuter-spotting-scopes.html

Cheers for your further input.

The main advantage (as I see it) of the MAK over a refractor is the size... The C70 gives me 750mm focal length in just 280mm.

I know that refractors are said to have the edge for solar system viewing... But at double the size, that's hugely expensive in terms of my most crucial concern of space saving.

... Is there some other benefit that I'm overlooking?

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A Red Dot Finder is a zero magnification pointing tool that uses a coated glass window to superimpose the image of a small red dot onto the night sky. Once you align this with your scope it allows you to find the thing you're trying to look at. Some (more expensive) options project rings of known diameter, rather than a dot; this is useful in star-hopping.

Edit: And if wanting low cost and really portable, I'd consider binoculars and a tripod of some sort, as mentioned above.

Thanks for the info on the red dot finder.

Re binoculars... Thanks again for that advice- I am hearing you guys loud and clear... But I just don't understand *why*... Like... If I've got a pair of binoculars, can't I just cut them in half along the bridge, so I have the same optical power, but only a singe barrel, rather than two?? (Effectively, what I think I'm originally proposing??)... What's the advantage of having two chambers?

... Sorry if this is a stupid question! I'm an uber-noob!

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Cheers for your further input.

The main advantage (as I see it) of the MAK over a refractor is the size... The C70 gives me 750mm focal length in just 280mm.

I know that refractors are said to have the edge for solar system viewing... But at double the size, that's hugely expensive in terms of my most crucial concern of space saving.

... Is there some other benefit that I'm overlooking?

The only thing you might be overlooking is the MAKs central obstruction which if was 20% for example puts its light gathering at 56mm equiv or less that means even a pair of 50mm binoculars or a 60mm refractor /spotter could out perform it on dim objects.

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The only thing you might be overlooking is the MAKs central obstruction which if was 20% for example puts its light gathering at 56mm equiv or less that means even a pair of 50mm binoculars or a 60mm refractor /spotter could out perform it on dim objects.

That's a very valid point and I was indeed overlooking that!!! Many thanks!

Still- the fact that the MAK is just 280mm is a huge boon for me. Especialy given the 750mm focal length.

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That's a very valid point and I was indeed overlooking that!!! Many thanks!

Still- the fact that the MAK is just 280mm is a huge boon for me. Especialy given the 750mm focal length.

I agree this is why your question which seems simple enough is a toughy, binoculars like maks have folded optics to make a smaller package spotting scopes are a bit like half a binocular but without the reduction in size.

I would suggest you try all options if you can though before you buy as you said it might be with you for a few years.

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The only thing you might be overlooking is the MAKs central obstruction which if was 20% for example puts its light gathering at 56mm equiv or less that means even a pair of 50mm binoculars or a 60mm refractor /spotter could out perform it on dim objects.

This is wrong and a common mistake!  To get the same area as the MAK less the obstruction the equivalent scope would be around 68 mm. (assuming my maths is correct!)

The 20% obstruction by diameter is only a 4% obstruction by area.

Cheers,

Chris

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This is wrong and a common mistake!  To get the same area as the MAK less the obstruction the equivalent scope would be around 68 mm. (assuming my maths is correct!)

The 20% obstruction by diameter is only a 4% obstruction by area.

Cheers,

Chris

OOPS i stand corrected well spotted..

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There is another consideration, cool down time.

A Mak needs a while for the tube to cool to give the best views.

A refractor I gather (never tried one) needs far less cooling time if any.

Things that I like about the c70.

Very small, very light, seems fairly sturdy

Images are the right orientation.

Responds well to better eyepeices.

Went as hand luggage through Gatwick with no issues for me.

The moon looks cracking.

Jupiter moons visiable, but planet too noisey to see bands but I was viewing in a really bad situation, through a window by a radiator lol

What I dislike.

The zoom eyepeice is not very good when zoomed anything past about 25% it looses detail quick when used on the moon.

The zoom eyepeice is actually quite big and needs to be stored somewhere when removed and it has a cover tube too.

Once removed you then have to fit an adaptor ring for 1.25 eye peices. More pocket junk when observiing.

The tube is difficult to sight along, in day light an empty pen tube rubber banded to the side works, but this is useless at night, so for night use you do need at least a red dot finder.

FOV is narrow.

Eye placement is very particular, you must be where your eye needs to be to see down the tube. This has meant I have not managed one afocal photo hand held.

You could also consider, and bare in mind for day time use you need to also have a star diagonal (so look for deals with one) otherwise terestrial viewing maybe upside down etc. All pretty light but 2 are are heavier then the c70 and also longer.

Celestron c90 80mm mak

Celestron 70mm travel refractor

Skywatcher Startravel 80mm refractor

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yes it is a typo :)

I would not personally get a dedicated spotter that could not take 1.25 eyepeices too.

The c90 is considerably heavier and a bit bigger and it is the same tube as the skymax 90 which is popular I gather. Not sure if the FOV is even tighter.

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Can I ask a very basic question, which is 'what do you want to see?'

This may seem obvious, but actually there is quite a difference in requirements between solar system planetary observing and DSO/widefield 'stuff'

The mak could potentially be ok on planets, but there are maybe other options such as an ST80 achro frac which is still quite small but at a dark site would give nice widefield views.

Somewhere I do have a small 65mm mak and it is quite disappointing on anything other than the moon so be aware of the likely quality, and be realistic about the magnification you can achieve.

Stu

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I will try and explain the difference between binos and maks in terms of observing quality, but some aspects are less "technical" than others.

First of all, the central obstruction presents some disadvantages. A 25% CO will reduce the area by over 6%, resulting in 6% less light (not a great deal), 6% less resolution (a bit more of a deal) and quite a lot less contrast (a biggish deal). In my experience, you cannot push the magnification on obstructed designs quite like you can on refractors.

Another issue is comfort and convenience, which can't be quantified. With binos you do not have to faff with eyepieces or even much with focus. You don't need a finder. You don't need slow motion controls. You just observe and pan the sky. You have to try them to appreciate this.

I understand what you're saying about binos having an "unnecessary" extra barrel, but using two eyes is so much nicer and more natural than squinting through an eyepiece. More comfort means you see more. You could say binos have the disadvantage of only one magnification, but you're not going to get very high mags on a 70mm aperture anyway.

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