magnification question (am I missing some part?)

[crovax]

Hi, yesterday I had a chance to test my new telescope and I wonder if I get the correct magnification. The shop where I baught it says that I am going to get 260х. Yesterday I put in 10mm eye-glass and barlow-lens and the saturn was about the size you see in the image (the image is not mine, I found it on the web).

So am I doing everything correct and that's how it is supposed to look at 260x? My telescope is Sky-Watcher 1309EQ2 (900mm/130mm). Or may be I am missing some optional thing to get the max magnification?

[Doc]

Thats not at x260. Your scope has a focal length of 900mm so by putting in your 10mm and barlow you have achieved x180.

To get X260 you will need a 3.5mm eyepiece.

At x260 your scope would be unusable anyway the image quality combined with the poor seeing here in the UK would make it impractical.

[crovax]

Yeah, I guess the scope will cause too much problems. At 180x I had some pain with locating saturn and it was rather quickly running away so I had to track it. But will I be able to get rather good images of other objects (galaxies for example). It's just I was expecting saturn to be larger and now I wonder if I will be able to see details in other objects (spiral arms, etc)

[RichieP]

Hi Crovax,

The maximum useful magnifaction achieveable by any scope is, as a rough rule of thumb, 2 X the diameter in mm, limited by the unsteadiness of the UK skies! It's difficult to get more then 300x in this country, and then only on nights of very good seeing.

So that's why your telscope, with a diameter of 130mm, claims a max magnification of 260x. It does not mean that the eyepieces supplied with the scope will necessarily be enough to acheive this.

On nights with clear seeing, I think you could achieve this, with a 3.5mm eyepiece, or a 7mm eyepeice and a decent 2x barlow. This is on those exceptional nights however - most of the time you would be limited to 150x to 200x.

In terms of what you will be able to see with your scope (and the Skywatcher 130s are very good beginners scopes) then I would expect it to perform well on moon, planets, open clusters, globular clusters and some of the brighter nebulae. Unless you have very dark skies, I would not expect to see detail on galaxies however as this requires more apeture. It's nice just to find galaxies though, especially if you make out the rough shape (round, cigar shaped etc).

Have you thought about a RA motor for your EQ2 mount? Then you can let your mount track the object whilst you concentrate on viewing the object. The longer you look at something then the more detail can come out.

regards

Richard

[crovax]

Yeah, I've been thinking about that motor. I think if I decide to buy a better eyepiece, I'll take the motor too. By the way will it help in locating the objects too? So is the following scenario possible:

I locate an objects with 25mm and center it, start motor, switch to 10mm, center, switch to 3.5mm, center, switch to 3.5mm+barlow?

P.S. I am not located in UK. I live in Kyiv, Ukraine and probably our sky is not that unstable because we're not surrounded by seas. That's just a guess though, I really don't know how that can me measured.

[RichieP]

Yes that is a good way to do things - locate things at your lowest magnification, lock your axis with the clamps and have the RA rotor running and then keep on increasing the magnifcation until the image starts to deteriorate, making minor adjustments to keep the image centered if needed.

I think a 3.5mm and a 2X barlow would be too much though (514x). Remember, astronomy isn't about magnification, and a brighter, sharper, smaller image always beats a dimmer, larger, fuzzier image. I find a tend to do most of my observing around the 100x mark

I assume the Ukraine isn't as damp as the UK so you may get better seeing then we do.

[crovax]

Oh I see. Then I guess I'll stop at 7mm or 5mm eyepiece.

Regarding galaxy details. Wikipedia claims that this image (M51) is a sketch by astronomer who lived in 1845. I wonder how he managed to do it. Can it be that in 1845 he had a better telescope than me?

[RichieP]

That is a sketch by Lord Rosse who had two things going for him in 1845:

- skies with no light polution

- An aperture of 0.9 metres (36 inches)

[brianb]

Wikipedia claims that this image (M51) is a sketch by astronomer who lived in 1845. I wonder how he managed to do it. Can it be that in 1845 he had a better telescope than me?

Better? Bigger, certainly - he had no less than 72" (1.8m) of aperture! Leviathan of Parsonstown - Wikipedia, the free encyclopedia

To get a good view of deep sky objects you need a low magnification - about x4 or x5 per inch of aperture - as this give the brightest, most contrasty image.

Modern scopes are much more efficient than Victorian reflectors with speculum metal mirrors, even so it is asking a lot of any scope under 24" aperture to give a view as good as that shown in the sketch above.

[crovax]

Haha, yeah that makes sense. For some reason I didn't imagine that he had such a monstrous telescope

[adamsp123]

You know that was Lord Rosses' grap and go scope

[Hipolito]

P.S. I am not located in UK. I live in Kyiv, Ukraine and probably our sky is not that unstable because we're not surrounded by seas. That's just a guess though, I really don't know how that can me measured.

It doesn't look that bad in the Ukraine ... not compared to the UK, Holland, France, Germany, Italy, Belgium, Poland You should be able to get some nice dark skies (see map below)

http://www.astro-travels.com/pictures/Europe-Light-Pollution.jpg

[The Warthog]

I have seen that galaxy in a 25" scope, and the spiral arms are quite distinct. It is still a smudge in my 6" scope.

[crovax]

It doesn't look that bad in the Ukraine ... not compared to the UK, Holland, France, Germany, Italy, Belgium, Poland You should be able to get some nice dark skies (see map below)

http://www.astro-travels.com/pictures/Europe-Light-Pollution.jpg

Yeah true, the skies are quite dark here. However there is a stupid lamppost exactly on my corner of the street but I guess it doesn't make much pollution (they are quite rare and there is max 10-20 in all the village). I can't wait for the weekend to find something new on the sky

I have seen that galaxy in a 25" scope, and the spiral arms are quite distinct. It is still a smudge in my 6" scope.

25" is quite much. Are such telescopes widely sold to public? Could you give me link?

[crovax]

By the way how do you seek nebulas and galaxies? They are not visible with naked eye, right? Will I distinguish them from stars in my 25mm eyepiece? I mean when I was seeking Saturn I first thought that it is a star and moved away from it. Then my friend went and checked Saturn position in the laptop. Then we located it again and when I was going to say "it can't be Saturn, it's just a star", I noticed tiiiiny circles around it. Of course when we put Barlow and 10mm it became obvious that this is not a star.

So now when I recall all the problems we had with Saturn which is very well visible with naked eye I can't imagine what problems we will have with not-visible objects.

[Doc]

Galaxies might be a struggle but you should see M31 and maybe M81 & 82 as for nebulas you should see M57, M27 and M42 when it comes round again.

Seeing these takes practise, what you need is good star chart or planetarium software, a red torch and make sure your finder is well aligned.

Then it's just a matter of star hoppping to your target of course this is only relevant if you haven't got go-to.

[kniclander]

if you have dark skies (and it sounds like you do) you should be able to see most of the northern hemisphere messier galaxies but only as faint smudges. As Doc says, starhopping is the way if you don't have goto and believe me finding a galaxy by starhopping is incredibly rewarding. the only thing I would say is that i found starhopping impossible with the supplied finderscope because it inverts the image so nothing looks like it does on the map. if you can get a correct image finder, that should make things a lot easier.

ps there are at least 6 reasonably bright galaxies in leo which you might well be able to see at the moment.

[crovax]

Thanks for those M-objects, I'll try to find them on the weekend. I am using Starry Night Pro software and I can say that it is very handy.

I was not able to find a red lamp in the store I use. If I ever see it somewhere for sale, I'll get it. However last time I used my 9" netbook with minimized brightness and it acted as a torch quite well.

I don't have goto because it doesn't sound like fun for me. Before the last weekend I knew only Big Dipper and Small Dipper. And now I can find Cassiopeia, Ursa Major (instead of Big Dipper), Vega (didn't have time for Lyra because of clouds), Arcturus, Leo and presumably Sirius. Finding all that stuff manually was a big part of the fun. I am just afraid that I won't be able to tell M-objects from stars

The inverted seeker is painful but I almost got used to it (which doens't mean that I won't replace it as soon as I find a normal seeker). That's rather easy: if you want to move seeker image down, you move telescope up. THe same goes for left-rigth

[Doc]

You will easily recognise galaxies from stars. Just have a look for M31 to see what I mean.

All those Messiers I mentioned look nothing like stars.

[crovax]

Yeah, I'll try to. Andromeda was the first thing I was going to look for however I am not sure if it's high enough. The thing is that I have forest in that direction (and I don't want to stay up till 5a.m. when it gets higher). I'll try to find it but may be I'll have to wait till June-July to see it.

[brianb]

I was not able to find a red lamp in the store I use.

Can you find red lacquer of the sort that women use on their fingernails? A couple of coats of that turns a "white" torch into a red one....

M31 is starting to get fairly well placed, at my location it was already 23 degrees high in the north east (azimuth 50 degrees) at 0135 UT this morning when the sky was starting to brighten (end of nautical twilight).

[crovax]

Yeah, it's location is quite well in the morning. The problem is that I am owl-type so for me it means that I will have to wait till the morning because going to bed at 1-2am and getting up at 4-5am sounds painfull. Of course I may try to achieve a heroic deed and go to bed at 10-11pm but I am not sure if I can.

[crovax]

I've been looking in the internet for ep-s and found some at ebay. However I am confused a little. Take a look at these:

Meade 5 Five Piece 1.25" Telescope Eyepiece Set - New!! - eBay (item 270393722967 end time May-26-09 12:58:39 PDT)

Zhumell Telescope 1.25 Inch Eyepiece and Filter Kit - eBay (item 270396474196 end time May-27-09 11:59:08 PDT)

Could you tell me is there something wrong with them or with quality? You see, they are sold at 39.59$ and 65$ and I don't know if that's normal. Often ebay is a better place to buy than my local shops but the difference in price is huge. So for example in my shop 'Meade 1.25": Pl 15 mm, Pl 9 mm, 2х Barlow; set costs 163 USD.

[Wobbly Bob]

Thanks for those M-objects, I'll try to find them on the weekend. I am using Starry Night Pro software and I can say that it is very handy.

I was not able to find a red lamp in the store I use. If I ever see it somewhere for sale, I'll get it. However last time I used my 9" netbook with minimized brightness and it acted as a torch quite well.

I don't have goto because it doesn't sound like fun for me. Before the last weekend I knew only Big Dipper and Small Dipper. And now I can find Cassiopeia, Ursa Major (instead of Big Dipper), Vega (didn't have time for Lyra because of clouds), Arcturus, Leo and presumably Sirius. Finding all that stuff manually was a big part of the fun. I am just afraid that I won't be able to tell M-objects from stars

The inverted seeker is painful but I almost got used to it (which doens't mean that I won't replace it as soon as I find a normal seeker). That's rather easy: if you want to move seeker image down, you move telescope up. THe same goes for left-rigth

Thats the way, learn the the sky using your software as a guide. Try locating Hercules and M13, this should give you a good idea what too expect. Try a pair of 10x50 binoculars, you will be amazed at what you can find with them.

The trouble with high magnification is the view will be dimmer and the object will be very hard to keep up with without a good solid tracking mount.

[crovax]

Yeah, I've got binoculars however I don't know how good they are. The only pieces of text I was able to find say "119m auf 180000m" and "field of view 56^o 50'". Anyway I remember how I pointed them at sky last year and was lost in terrible number of stars I was able to see. So I guess they will be fine for finding objects.