Tightass wants a first telescope

[narky (Sam)]

Hi everyone,

I've been looking for a first telescope for about 6 months. The more I look the more confused I am. Apologies for starting yet another "my first scope thread".

Firstly, I don't want a dob. I know that for cheap stargazing it is the best option (aside from binoculars), however I'm pretty aware that the telescope will more be looked at than looked in. If I will look at anything, I"m guessing the Moon and the planets will be viewed most. Will attempt to look at some of the messier objects. Not sure what i'll see. Not big on deep space (mostly because I don't want to drag around a monster). Has to fit into my little sports car for away trips.

Second, I imagine I'll likely be looking at things out my window in daytime rather than viewing the sky. So I really need something that won't flip the image upside down (or if it does, is there a way to add another mirror to flip it right-side up). So i'm confused if I should be looking for a relecting or a refracting telescope?

Third, i'm currently unemployed and have only a limited budget. I want to spend less than $400.

I have been checking out Andrews and Bintel (i used to look at a site with GSO scopes, but I can no longer find it), so I've figured I'll stick with Skywatcher.

I looked at http://www.telescope-simulator.com/i...d=45&Itemid=57 but it seems to indicate I won't see anything with any of these scopes (however reviews talk about seeing details on jupiter, the rings on saturn, and polar ice caps on mars) .. what might I see or not see?


Here's what I'm considering.

Refracting:
102 x 500 AZ3 package $399
90 x 900 AZ3 package $249
90 x 900 EQ2 package $299
80 x 400 AZ3 package $269
Black Diamond 90mm x 900mm AZ3 A$349.00

Reflecting:
130 x 900 EQ2 $399
Any help?

ALso, i'm unsure about the mount, i don't mind fidling, but the idea of an EQ mount seems appealing (or am I too cheap to consider such a thing as I won't be spending enough $ to get anything workable) ??

Let me know.

[Alchemy (Clive)]

Just about any scope will get you rings on Saturn, refractors cam get a corrected view diagonal for terrestrial use.
For Astros use a eq wih a drive is best so once you have the object you can look for a,while
For terrestrial I think an alt az is best.

[narky (Sam)]

Originally Posted by Alchemy

Just about any scope will get you rings on Saturn, refractors cam get a corrected view diagonal for terrestrial use.
For Astros use a eq wih a drive is best so once you have the object you can look for a,while
For terrestrial I think an alt az is best.

Given the way these telescopes work, am I better off with a Refracting telescope for terestrial viewing because there is nothing blocking the light?

Which is more an issue for terrestrial viewing, coma or optical aberation?
What about for viewing the moon or the planets?

Plus I assume for looking out my window it will be easier to view with the eyepeice at the back, however more painful for skywatching as If I'm looking up i'll have to be near the ground ? I've read many times people suggesting refractors are better if they have a 90 degree mirror attached. (which makes sense)

Also, is there less maintenance with reflecting scopes?

I'm worried about collimation. If needed do I need to purchase a laser collimator or is there a simpler way to do this.

[dannat (Daniel)]

if it was me i would probably get the 90x900 az3 -siple mount sets up in seconds & can give quick looks - no need to worry about collimating

[Alchemy (Clive)]

You will not notice the obstruction in a reflecting scope when looking through it, however using a reflector for terrestrial applications the view is flipped or upside down.... Not so with a refractor. Coma , aberrations etc will be present in any cheap scope, but really matter more for photography, the discerning viewer wil purchase a much more expensive scope anderhaps add something like a paracorr.

On a really cheap scope you may notice a purplish edge to bright objects like the moon, again you get what you pay for.

Reflectors need collimating, refractors don't.

Given your desire to do some terrestrial work I would stick to binoculars or a refractor.

[NorthernLight (Max)]

The 90x900 on an alt az mount would be my advice as well. An eq-mount is absolutely painful for terrestrial and very counterintuitive for a novice. But given that the refractor is about a 1 meter long with its focuser and dew cap it might be too big for you and you could be better of with the 100mmx500mm. Both will more or less show you the following:
Regarding the planets: don´t expect too much of such a telescope and don´t rely on a computer programm that tells you what you could see through it under optimal atmospheric and light polution conditions. those programmes work with high resolution images taken with completely different scopes and expensive cameras. the size and resolution of jupiter in the 90x900 isn´t like the picture on the top right of this forum page. You will see the moons as tiny dots on its left and right but no red spot and hardly any cloud bands. As for saturn, you´ll see a tiny roundish thing with little attachments left and right (the rings are edge on for the next years). Venus is very bright and featureless but you can observe its phases (like the moon). Mars would be slightly bigger than a star and somewhat orange-thats it. The moon and the sun (you need filters for both but NO EYPIECE FILTER for SOLARWATCHING-APERTURE FILTER!). The moon, if you haven´t seen it through a telescope will blow you away and when you read the moon columns in A S&T or learn more about it elsewhere you can have a lot fun discovering and studying things-the different phases of the moon bring (almost) every night a different scenario. The sun spots are picking up as well. I have seen my first recently through my telescope and found them amazing (..I now want a coronado..).
Deepspace wise, it all comes down to where you are in terms of light pollution. If you are far out in the country and know where to look at, you´ll defenitely find some great open and globular clusters, a few nebulae and perhaps some dim galaxies.
Terrestrial watching is certainly no problem with it. forget about all comas and aberrations-that is nothing you would notice especially during the day.
But don´t forget to fit some decent eyepieces into your budget, a diagonal and a barlow lens (extends your focal lenght by a factor). I´d suggest a 2xbarlow, a 10mm, a 20mm and a 30mm eyepiece (plössles). The scope brings about 180x maximum useful magnification (apperture in mmx2). with these eyepieces you get 6 different magnifications (mag=telescope focal length divided by eyepiece focal lenght) from widefield to maximum. But don´t go for the cheapest stuff, rather buy one less-its the eyepiece (or occular) that determines the quality of the image you are viewing (crisp and contrastrich or soft and dim).
Have fun with it and be careful not to get hooked too much!
Cheers

[michaellxv (Michael)]

From what you have said I would agree with the others. The 90 x 900 AZ3 is your best bet.
It will work fine for the planets and moon. As others have said you won't see much detail on the planets but the moon it great.

I have an 80x900 and have no problems with open clusters and globular clusters. There are some bright nebulae that look good too. Fainter objects can be found at a dark site but will be no comparison to a bigger DOB.

A refractor does put the eyepiece down low but a 90 degree mirror fixes that.

[narky (Sam)]

Originally Posted by NorthernLight

you could be better of with the 100mmx500mm.

I was originally thinking this, simply because it will take up less space in my bedroom. it has to sit between my bed and the wall where there is only a little over a metre space.

But after checking the quality of images from that silly simulator site, I didn't seem to see anything and figured I needed to avoid the shorter scopes. Will there be any noticeable difference with using a shorter scope?

I live pretty close to the centre of Sydney so light polution may be a slight issue. However I plan to go to the Hunter Valley and take my scope with me. (Also heading to Tasmania soon if things go to plan where I hope viewing will be good).

What filters are best for the moon/Sun ?

Thanks again, wonderful response.

[Screwdriverone (Chris)]

Hi Sam,

Yup, the 90 x 900 on the AZ3 seems the best mix of size, ease of use, terrestrial capability as well as performance. For $249 its well within the budget, HOWEVER, it seems its out of stock.

On the same page is the Black Diamond version (not ED) but much SEXIER paint job but I think the same visual design and performance. But paying $100 more for the speckly Black Diamond paint job may be a bit silly.

Check with Andrews to see if they can rustle up a 90x 900 AZ3 package even though the site says they dont have any, you never know.

$249 is a great price to get you started. Stay away from EQ mounts if portability is your thing as AZ are a doddle to carry and set up. EQ needs to be roughly polar aligned and thats not much fun if you are starting out on the limited budget you have.

Nothing to do with a refractor on an AZ, simply extend the legs, plonk it down and then off you go, cruising the night sky. You will be surprised at what the scope can pick up.

The 102 x 500 is shorter and has an F5 focal length which means its more widefield (not as narrow view as the 900mm one at F10) BUT the smaller focal length means you cant get up as close to say a planet or smaller Deep sky nebula etc with a shorter focal length. For example, the 900mm scope with a 10mm eyepiece will give you 90X magnification without any sort of barlow magnifying lens. With the 500mm scope, that equates to 50x magnification (FL divided by EP) so therefore the view is close to twice as big as the 500mm one. As a rule of thumb, you will only get about 2-2.5 times the aperture of the scope as the maximum magnification that is usable, so that means the 90 would be about 180x-225x and the 102mm would theoretically give 200x - 250x BUT to get that from the 102mm, you would need a 2mm Eyepiece or a 5x barlow on the 10mm I mentioned before, which is NOT going to work. On the 90mm, the longer Focal length means to get 180x, all you need is a 10mm eyepiece and a 2x barlow (recommended) to get to a pleasing, yet still usable maximum of 180x magnification.

Black Diamond complete "AR" refractor packages!!

90AR-AZ3 A$349




Cheers

Chris

[narky (Sam)]

Thanks everyone.

Will head out to the store and take a look.

Greatly appreciate the feedback. Quality forum (i posted here about a year ago, but either my account was deleted or I was using some wacky email address I can't remember).

Looks like I"ll be checking out the Black Diamond 90 x 900 (hopefully it comes with something extra aside a different paint job).



Oops, forgot to mention Chris' post. Awesome. Thanks for clarify so much for me in one post. (Thanks to eveyone once again, I think i already thanked everyone else individually in my other posts).

[narky (Sam)]

Oh Noes,
I found another possible scope.

So based on what i've seen so far the SW 90AR for $349 seems like the best available choice for me.

Then I found this :
Celestron NexStar 80 SLT
$399 ...

Thoughts ?

[NorthernLight (Max)]

$50 more for a smaller telescope.

From the add it did not become obvious whether or not the diagonal and/or any eyepieces would be included, so it appears as if the aditional costs are justified by the computerised mount only.

The usefulnes of such mount may be questioned though I have to admit to love my go-to mount. Here is a thought to the mount:

80mm aperture limits the ability to observe dim deep space objects (DSO´s) even more than 90 or 100mm, so what you are really in for are planets, moon, sun and the DSO´s that can be seen with the naked eye under good skies (they will resolve much better with the telescope). So what the mount does is either slewing automatically to database objects the user can already see or to database objects that the user will not be able to see with this telescope. Autotracking could be a valid point as it ensures that an object does not move out of the field of view (due to earths movement). But this is easily achieved manually (and without aditional costs for batteries). At least it offers a little amazement when the telescope starts moving by itself. The decision is yours.

Filters: a moon filter will be necessary to reduce the very bright glare and increase contrast. A sun filter will be necessary to safely observe this star. The baader sun filter foil works great and is very inexpensive: http://www.astroshop.eu/filter-foils...-baader/p,2718. You would have to make a fitting filter for your telescope but this can be done with a bit carboard from a calender and some glue. The rest of the foil that you don´t need will sell well amongst others on the forum. The filter cuts out 99,99999% of the incoming light so it is safe to look directly in the sun. But be careful, if the filter falls off whilst the observation your eye will be irreparable damaged in less than a quarter of a second.
I think colour or special bandwidth filter would not be necessary given the small aperture.

Cheers

[michaellxv (Michael)]

I have the earlier version of the Celestron. Add to this cost the ongoing supply of AA batteries (not recommended) or another ~$100 for a jump start battery to run it.

It should come with 2EP and a diagonal.

The big catch for you setting it up from your bedroom is you will have trouble finding alignment stars to set it up.

Also, it would be a pain in the A.. to use for terestial as you can't just grab it and swing it round to where you want to look. You must drive it with the motors.

[astro_nutt]

Hi Sam.
If you are worried about colour correction, (chromatic aberration, i.e., seeing a blue-yellow halo around a bright object), when using a achromatic, (doublet lens), refractor. You can purchase a "minus violet eyepiece filter" which will help correct this to some degree.
Cheers!

[astro744]

Originally Posted by astro_nutt

Hi Sam.
If you are worried about colour correction, (chromatic aberration, i.e., seeing a blue-yellow halo around a bright object), when using a achromatic, (doublet lens), refractor. You can purchase a "minus violet" which will help correct this to some degree.
Cheers!

I think looking through a window will give Narky more to worry about than just colour correction, (unless it's optical grade glass that also corrects for off axis aberrations).

[Steffen]

The 80mm f/11.25 won't show much colour, by virtue of geometry (it's well within the Fraunhofer criterion). The 90mm f/10 on the other hand needs colour corrected optics in order to be achromatic.

Regarding DSOs in small scopes, while more aperture will obviously show you more it isn't true that you'll only see naked-eye DSOs in an 80mm refractor. My 80mm f/7 ED shows plenty more than that, including all Messier objects and then some. An 80mm lens collects a lot more light than a 7mm pupil.

Cheers
Steffen.

[narky (Sam)]

Originally Posted by astro744

I think looking through a window will give Narky more to worry about than just colour correction, (unless it's optical grade glass that also corrects for off axis aberrations).

Hahahah ..

To clarify, I'll only be looking through the window in the day time for terrestrial viewing.

Night time I'll be dragging it out side. And will take it with me when I head to the country for little holidays.

I do like the idea of connecting a scope up to my laptop and getting a guided tour, but I suspect then I won't really learn a great deal. It's a tradeoff between being shown more than i'll likely find by myself but remembering little of it, or endeavouring to find them myself and having a greater sense of achievement, plus having what I consider to be a less ugly looking telescope (the Nexstar one seems a little ugly).

I was planning to goto the Hunter Valley to drink myself blind, so a goto telescope would be an advantage then. Considering i'll use it more indooors, I'll guess I should avoid it. Probably better I spend that $50 on something else.

[taxman (Matt)]

Really though, how many of us, the first time we looked through a telescope even noticed chromatic abberation?

Amateur astronomers have a tendency to get a little weird about numbers and "facts", sort of like audiophiles...

The 70mm of aperture gives you 5 magnitudes better than the naked eye & a casual viewer will see plenty.

[astro744]

Just to clarify image orientation.

If you use a refractor with no diagonal (extension tube will likely be needed) to look at the horizon and you are standing on your feet with head up with your eyes parallel to the horizon the image you will see will be upsidedown (NOT reversed/mirrored).

If you now removed the extension and add a mirror diagonal and look down into the telescope whilst it is pointing at the horiozon and you are standing behind the telescope facing the same direction that the telescope is pointing then the image will be rightway up but mirror reversed.

RULES OF REFLECTION: Any odd number of mirrors produces a mirror reversed image. Any even number of mirrors or no mirror causes right way round images but they may be upside down depending on how you place your head. ie. if you observe sideways the image is rotated 90deg. If you rotate the diagonal the image is also rotated 90deg.

For corrected terrestrial viewing you need a prism diagonal that has multiple internal reflections to right the image. These are usually 1.25" but 2" versions are available although expensive.

Normally I would provide a useful web link but this time I will warn you of a not so useful web link:

http://www.spaceref.com/telescopes/I...side-Down.html

The UPSIDEDOWN image is WRONG as it is also reversed. UPSIDEDOWN should be rightway around and any stars seen should match star charts.

[narky (Sam)]

Bought the Starwatcher 102 x 500 today for $399 from Andrews.

Reasons for this were smaller size means it fits next to my bed better.
F5 seems better for daytime terrestrial viewing.

Comes standard with a 45 degree erect prism so everything looks normal (and they kindly threw in a moon filter because they didn't have a box to put it all in).

Luke from Andrews was very friendly and I'd recommend them to any other newbies buying a scope.

Thanks again everyone for your help. Can confirm that right now in daytime I can't notice any imperfections at all even through the flyscreen everything looks crisp. The AZ mount is definately what I needed, so nice and easy.

Really appreciate the help from everyone. The advice here really helped me narrow down what I needed. again.