Newby advice please - Astronomy / Astrophotography

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Newby advice please - Astronomy / Astrophotography

Postby NWPS4 » Sat Sep 17, 2016 12:03 am

Hi All,
I have been fascinated with the heavens for years now and finally after developing my family to an age whereby I can finally enjoy life to the extent that I can also have a hobby :)

I am possibly jumping into this feet first but I am looking to purchase my first "proper" telescope (had the National Geographic kids edition up to now) with which i can not only view at the moon, planets and possible deep space but also some astrophotography of them as well :)

I have read quite a lot over the past few months as to which scopes are recommended and wanted to ask my own question so to speak..... as i will be a beginner and on a relatively small budget (hopefully I can also rely on second hand units) I have come to the predicament of choosing either a Celestron 102 SLT or a Nexstar 4SE (would love an 8SE but I still have to feed my kids!)I seem to only have heard the Celestron's being topic of conversation. I think a goto mount is a necessity for what I would like to use but am unsure what will be best. Please can someone put me out of my misery and let me now the pro's and cons of both scopes as well as potential other candidates? I would not only like to connect my camera but also my Macbook Air to control / view images

I will be using a Nikon DSLR (hopefully a D5300 or D5200) with 30 sec exposure/ ISO 800 for pics

all advice would be greatly appreciated.
NWPS4
 
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Re: Newby advice please - Astronomy / Astrophotography

Postby Aratus » Sat Sep 17, 2016 4:11 pm

Hi

Briefly, the 102SLT is a 4" refractor and the 4SE is a 4" 'reflector' (SCT).
The refractor has a focal length of 660mm and the 4SE a focal length of 1325mm. Therein lies the main difference. Use a 25mm eyepiece on each telescope and you will get different results. With the refractor you will get a bright, wide field view with a magnification of 26x. With the reflector you will get a dimmer, narrower view and a magnification of 53x.

So, the refractor will give brighter deep sky objects than the reflector. The reflector will give bigger views of the planets and the moon than the refractor. One isn't better than the other, they are just different.

To complicate things, with additional lenses it is possible to increase the magnification of the reflector or to widen the view of the SCT reflector so making each more versatile to a certain extent.

Refractors require no adjustments, but an SCT can need tweaking from time to time if jolted about. (That might be an issue if you are transporting them from place to place.) Either will connect to your camera.

In the end you need to make a choice, but they are both fine telescopes, and I don't think you can make a 'wrong' choice. Either will give you hours of pleasure. Bear in mind the advantages of each telescope and that at some point you could get additional lenses to broaden the range of objects.

Wait a while and I'm sure other people will come in on this and give you their opinions, and also tell you about other choices of telescope, and also about ways of getting bigger telescopes more cheaply.
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
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Re: Newby advice please - Astronomy / Astrophotography

Postby NWPS4 » Sun Sep 18, 2016 12:58 am

Hi Aratus,
Many thanks for the information, it is a great help in trying to understand what I "thought" would be a straight forward hobby!
From the information you have provided I think I must either make a decision what I wish to concentrate on OR have two telescopes to allow me to do what I want. (it maybe that I am currently expecting too much too quickly!) - Is it possible to mount both the 102 SLT and 4SE on the same mount depending on what my requirements are at the time?
I have been researching some more tonight and have found the following webpage which seems to steer me towards believing that the 4SE is the superior unit - (wont let me put the address in as looks too much like spam apparently!)

Also, for the Astrophotography, is there any recommendations on the camera used? I have tended to a Nikon but also considering a Canon EOS. Also any known drawbacks with piggybacking?

Many thanks for all your help and advice.
NWPS4
 
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Re: Newby advice please - Astronomy / Astrophotography

Postby Supercooper » Sun Sep 18, 2016 9:51 am

Hi there,

I'm sure my firend Aratus is alluding to me! :o)

I have a thread on this forum all about getting good equipment for peanuts. It's called 'Astronomy Doesn't have to be Expensive'.

astronomy-doesn-t-have-to-be-expensive-t128788.html

A brief look through there will give you food for thought I'm sure - Especially if you're ok with a second hand instrument.

I hope my little thread will be helpful for you.

There is also my Telescope Help website to trawl through - Especially my page on choosing a telescope.

http://www.ebay.co.uk/gds/Choosing-Your ... 783/g.html

Which includes a section on GoTo telescopes, also covered here>

http://www.ebay.co.uk/gds/Advice-for-Be ... 112/g.html

Any questions, please ask. Barry Cooper ;o)
________________________________________________________________________________________
For My FREE Telescope Help Website: http://supercooper.jimdo.com/

Using fab Helios f8 150mm Achromatic Refractor on SkyWatcher EQ5 - enjoing the views!
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Re: Newby advice please - Astronomy / Astrophotography

Postby Gfamily2 » Sun Sep 18, 2016 12:05 pm

A handful of quick comments.

If you're coming back to this with the intention of making a hobby of it, then seeing if there's a local astro society will be a good place to start. They often have observing evenings, where you can
a) have a look through a range of members' scopes
b) ask for advice for what works in your area
c) you may even be able to borrow equipment - most people have at least one scope they don't use much.
d) when you have your own equipment, you'll have people around who can give you hands on assistance.

You will often find telescopes on Gumtree or Preloved at good prices - recently someone had a Skywatcher 127mm Mak (like a bigger version of the SE4 you're considering) for £100, and I bought one earlier in the year for £190 - the list price is about £360. You should be able to get a larger scope for your budget if you're prepared to bide your time and keep your eyes open for a bargain.

For serious Astrophotography, you need to spend a reasonable amount on your mount - which should be Equatorial if you want to get images of the fainter deep sky objects. However, even with an Alt Az mount (like the two you are considering) you can get reasonable exposures of up to 30 seconds with a dSLR attached.

Finally; for visual observing, the general consensus is that you would get a crisper, more contrasty viewing with a refractor than with a similar sized reflector - but as Aratus has pointed out, because of the different focal lengths, the views will be quite different. The 102mm refractor will give gorgeous wide field images that are particularly good for open clusters and extended objects, whereas the SE4 will have a smaller field of view, which allows more magnification (for a given eyepiece) of planets, planetary nebulae and globular clusters.
The bigger aperture you can get (whether as a reflector or a refractor) the better you'll be able to see faint objects of course.

However, my first piece of advice would be to check out any local astronomy societies and see when you can join them for an observing evening.
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
(Not a moderator)
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Re: Newby advice please - Astronomy / Astrophotography

Postby Aratus » Sun Sep 18, 2016 3:47 pm

NWPS4 wrote:Hi Aratus,
Many thanks for the information, it is a great help in trying to understand what I "thought" would be a straight forward hobby!
From the information you have provided I think I must either make a decision what I wish to concentrate on OR have two telescopes to allow me to do what I want. (it maybe that I am currently expecting too much too quickly!) - Is it possible to mount both the 102 SLT and 4SE on the same mount depending on what my requirements are at the time?
I have been researching some more tonight and have found the following webpage which seems to steer me towards believing that the 4SE is the superior unit - (wont let me put the address in as looks too much like spam apparently!)

Also, for the Astrophotography, is there any recommendations on the camera used? I have tended to a Nikon but also considering a Canon EOS. Also any known drawbacks with piggybacking?

Many thanks for all your help and advice.


I wouldn't buy 2 telescopes at this stage. You can get a lot of observing from either a refractor or a reflector. There is no need to specialise, and you can make either kind of telescope work for the variety of objects available. I wish I could tell you that one is better than another, but there are so many factors to take into consideration. The 4SE is fine for a small telescope.

Using DSLRs has one big drawback, and that is that they are heavy. Stick a DSLR on to the end of a Celestron 4" of any kind and it will affect it. You may need to put weights on the other end to balance it. Piggy-backing, on the other hand will work very well. You need a bracket, but they are easy find and not massively expensive. Get one which locates the camera in the middle of the tube and you will be fine. In this manner you are using the goto mount to keep the camera on the object. Depending on the lens you are using you will be limited in the length of exposure with the alt-azimuth mount. This is because although the mount will track an object for hours, it will slowly rotate in respect to the sky. The more zoomed in on the sky the more quickly it becomes a problem. I don't find it a particular problem when piggybacking a camera, even with a 300mm lens, but you need to be aware that it is a limitation for that kind of mount if you want very long exposures. An equatorial mount gets around that, but they are harder to set up. I don't want to put you off the alt-azimuth mount (I have used one for 12 years without rotation problems) but it is a limitation if you want to go in for very long exposures.
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
Aratus
 
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Re: Newby advice please - Astronomy / Astrophotography

Postby Gfamily2 » Sun Sep 18, 2016 5:51 pm

In terms of the weight of the dSLR, I think you should be OK to put one on the back of either of those scopes because you can simply slide the whole OTA forward along the dovetail to re-balance it.

A bigger issue may be with getting focus on the 102mm SLT - the Celestron website sells a 1.25" T-adapter, but warns that 'fast refractors' may not be able to get focus without using a barlow.

http://www.celestron.com/browse-shop/as ... -t-adapter
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
(Not a moderator)
Gfamily2
 
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Re: Newby advice please - Astronomy / Astrophotography

Postby Aratus » Mon Sep 19, 2016 5:14 pm

Good point! My telescope predates the 'dovetail' fitting so I tend to forget that modern mounts are set up that way. I'm not sure with such a light telescope that it would be possible to slide it along sufficiently to reach the balance point with a heavy DSLR. It may do so, but even if it didn't, it would certainly take the strain off it. Using a barlow on the 102 for photography will rather spoil the main advantage of that telescope which is its wide field. Using a dedicated imager rather than a DSLR would solve that problem of course, but that is one more piece of equipment to buy. . .
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
Aratus
 
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