Telescope for Christmas... Help

[Jabell17]

I got a telescope from an antique shop for Christmas, and it has no information about the age or manufacturer. This makes it very difficult to put together, as I don't know where some bits go or if some are missing. Can anyone tell me what telescope it is? Or what I can do to find out?

[Jabell17]

I didn't realise that I couldn't include images when posting, sorry for being useless

[happy-kat]

Welcome

It might be because you have so few posts, Î can't remember if adding images comes with a certain level of post counts.

In the mean time you could download stellarium it is brilliant.

Is the telescopope a tube with a lens on the front?

Or is it an open tube with a mirror at the bottom?

[LukeSkywatcher]

To add images go to "more reply options" on the bottom right side and upload files. If the scope is from an antique shop, im guessing its a refractor.

[pipnina]

A refracting telescope should come with:

1. Tripod (unless it's meant to be hand held)
2. An eyepiece(s) (useless without one)
3. A star diagonal (highly preferable but can be used without)

It should also be cone-shaped, large at the front, narrow at the back with a big lens at the front.

A reflecting telescope should come with:

1. Tripod
2. Eyepiece(s)

It will also be an open tube, with a mirror at the front and a bigger mirror at the back. Cylindrically shaped.

If it is a cassegrain, it will be similar to a reflector, but with another lens at the front which also holds the secondary mirror. It may be shorter and stubbier. Unlikely to be found in an antiques store, though.

With eyepieces, higher focal length (the number likely written on the side of the barrel) means less magnification, unlike with camera lenses.

[LukeSkywatcher]

Antique shops will only sell brass refractors on a wooden tripod, im guessing.

[Jabell17]

It doesnt look that old, the shop sells a variety of oddities.

[pipnina]

It doesnt look that old, the shop sells a variety of oddities.

Is this everything that came with it? If so, you might need to get an eyepiece or two for it. Also, is that long tube coming out of the star diagonal what I think it is? (a barlow) If so, does it have 2x, 3x, or 5x on it (or other)?

Looks to me like n f5 or f6 refractor, maybe f8 or more if that rather extreme focusis anything to go by... It could be pretty good for planetary of it is a longer focal length, perhaps a nice entry to rich field gazing if it's a shorter length.

If you have any eyepieces, please post some photos here and if possible tell me what focal length they are. Also, measure the size of the front lens and see if there is inything inside the tube that might make the effective size of the front lens smaller. (Another image will help identify)

If you have any eyepieces, put the lowest power EP in, tell me the focal length (if possible) and measure the circle of light that comes out of it (with the scope pointed at an illuminated wall) in milimeters. All of this will help me (and others) help you and identify what you had best use this scope for or whether it's fit for the junk (hopefully not).

Merry christmas!

        ~pip

[happy-kat]

If your eyepieces have numbers on them the lowest powered one will have the largest number on it like 20 or 32 or 25 etc. (Of those examples the 32 is the lowest powered)

[Jabell17]

These were all it came with, so i believe that some pieces may be missing.

They read: 'HM 25mm', 'HM 6mm', and 'H 15mm'.

The lense is about 3 inches, and there is a smaller one about half way down.

The barlow has ×9 on it.

[Jabell17]

I have no idea where to put them on the telescope, so i cant do some of the things you asked.

[Cornelius Varley]

The long black tube (barlow lens) at the rear of the telescope can be removed by unscrewing the two small screws in the part below it (star diagonal) . One of the eyepieces can then be placed in the star diagonal where the barlow lens was located. Start with the eyepiece with the highest number on it, this will give you the lowest magnification. You can then work up to the higher powered eyepieces. The telescope tube is mounted in the yoke the wrong way round. Release the clamping mechanism holding the tube in the yoke and turn the telescope so that it is pointing the other way round. If you don't do this the telescope cannot be pointed a the zenith (straight up).

[pipnina]

These were all it came with, so i believe that some pieces may be missing.

They read: 'HM 25mm', 'HM 6mm', and 'H 15mm'.

The lense is about 3 inches, and there is a smaller one about half way down.

The barlow has ×9 on it.

x9!!!!???

That sounds pretty extreme. I might avoid using it. 2/3x barlows are the most common for a reason. That range of eyepiece focal lengths sounds reasonable without a barlow

Hmmm. That HM and H markings suggest some pretty crummy Huygens eyepieces. likely 0.9 inches in barrel size. You have other components in that image there.. Hopefully someone else on the forum can identify if those are adaptors of some kind.

Those EPs will not provide excellent views... But there isn't much more to do now in determining this scope. You said the front aperture was around 3 inches (76mm) was it slightly more or slightly less? Also, please try to measure the size of the circle of light with the 25mm EP in the focusser without barlow. (Accurate as possible, nearest half-milimeter will do) Do measure this I would use a ruler or tape measure, hold that up to the EP with the scope pointed at an illuminated wall and move your head back a little from the EP, that should give you the exit pupil and using some maths it is then possible to work out the scopes focal ratio and therefore what EPs you want to use with the scope.

I know i'm probably hassling you at this point, but hopefully some good will come of it.

Right, if the EPs won't fit in the black tube after the star diagonal, try removing it as cornelius said. If they still don't fit... That adaptor on the right that gets smaller half way down may be an adaptor from 1.25 inches to 0.9... If so, you are likely in luck since that means you can just buy a plossl or two and replace the Huygens (although, if you're happy with the huygens, no need to replace them)

Try removing that long black tube and replacing it with the possible 1.25 to 0.9 adaptor and put the EPs in that.

[Cornelius Varley]

This manual, though not exact, should help you http://geogdata.csun.edu/~voltaire/classics/tasco/12TE-2_manual.pdf

[Jabell17]

Thanks guys, I'll give it a go later. I misunderstood later and presumed that the barlow was the thing on top (I'm new to telescope lingo). There are no markings on the barlow.

[Putaendo Patrick]

Looks like a Japanese refractor from the 1970s era. Some were pretty rubbish and sold in cheap departments stores, others have surprisingly good optics indeed!

Looks like you have everything that you need to use it.

The two "blocks" you have are 1). a diagonal, which allows you to look down the EP and makes life more comfortable for astronomical observations, and 2). an errector prism - which allows you to see things the "right way round" for daytime viewing.

The three items marked HM25, HM15 and HM9 are Huygens Modified eyepieces and give you low, medium and high magnification respectively. As said not the best, but often very adequate (in the 1970s today's humble Plossl EP was an impossible dream for most amateur astronomers!). At some point check the diameter where they fit into the focuser or diagonal  - it will be either approx 0.9 inch or 1.25 inch. This will determine if and how you can upgrade these EPs should you want to.

The precise magnification of each EP is determined by the focal length of the telescope divided by the number on each EP. This focal length is the distance from the front glass lens to the focuser. For example, if it is 500mm your 25mm EP will give a magnification of 20 times.

The Barlow is the short tube, and will usually increase the magnification of the EP by a factor of x2 or x3. In some of these Japanese telescopes, the manuals recommended using the Barlow directly into the focuser without a diagonal.

The aperture is the diameter of the glass lens (not the dew shield). You have a small telescope so it certainly won't give you the detailed views of a much larger modern telescope. However, it should give you very nice views of the Moon, and smallish views of the planets. As I said at the beginning, you may be pleasantly surprised or wildly disappointed! I hope the former... Have fun!

[Alan64]

That's one of the better telescopes made in Japan during said era.  It looks to be either a 50mm or 60mm.  Does the telescope have an information label?  It's usually on the focusser itself, or on the optical tube, like this...

The telescope tube needs to be reversed within its mount.  It should appear like this...

I'd take a cotton swab dampened with window cleaner or rubbing alcohol and clean the lenses of the eyepieces.  Don't soak the swabs, just dampen them very lightly and remove the excess before attempting.

Again, it's one of the better telescopes made, so with the utmost care in its restoration it should give quite satisfactory views.

Can you take a shot of the front lens and post it?  Here's a shot of my 60mm, and of the telescope itself...

[Putaendo Patrick]

Alan64 - that's a sweet scope. Zanzutsu (z in diamond maker's mark) produced very nice optics. I'm currently tempted by a Zanzutsu spotting scope, like new in original box, made for Kmart under the Focal brand. Would be for day time observation, not astronomy, though. Dreaming is still free, I think!