Finderscope recommendation

[Lerxst]

I was out the other night and had a marvellous time with Jupiter thanks to my new Meade Series 4000 super plössls.

In another thread on SGL, I found a link to a site with september 2009 sights, and found this page which showed that M31 was slightly south-east of Cassiopeia (depending on where on this planet you are, I presume), and thought; hey, that'll be something!

But as I don't know how to operate the EQ3-2 mount yet with polar aligning and the RA/DEC axis, with the EQ3-2 pointing northwards as it should, I just swung the scope around and pointed it at Cassiopeia.

And here's the thing; I couldn't find Cassiopeia in the finderscope, embarrasing as it might sound. Since the image is upside/down and the finderscope (6X30?) that came with my Explorer 150PL gives a narrower view, I just gave up in the end.

I guess I found the constellation allright, but I couldn't recognise anything no matter how much and far I moved up/down and left/right; because of the narrower field of view, the image is upside/down (and horizontally mirrored?), and also because dozen of new stars are visible in the finderscope which is not visible to the naked eye.

So is there any trick and hints to navigating with the finderscope, or do I simply have to learn polar alignment and navigate the scope with RA/DEC first?

Or would I be better off with a new finderscope, say 8X50 or something?

[themos]

A red-dot finder is what you need.

[Macavity]

I think I gave up (For shame!) with an "equatorial", but recommend you persist? (Others will give better advice! <G>) But re. FINDERS, I found a RACI (right angle, correct image), 9x50 finder fairly intuitive.

HOWEVER, for basic "finding stuff", I fell in love with my Baader Sky Surfer V. You just... look though it, at the (implicit) 1x and correct-orientation, sky - And away you go! Worth the investment, tho'.

[Lerxst]

All right, red dot finder or 9X50 correct image - which should it be?

Personally I'd lean for the latter...

[John]

All right, red dot finder or 9X50 correct image - which should it be?

Personally I'd lean for the latter...

That would be my leaning as well - I fact I use nothing else on my 3 scopes (all alt-azimuth and non-GOTO).

I've tried quite a few RDF's and found the Rigel Quikfinder very easy to set up and use. It attaches using (very strong) adhesive pads so you can keep your optical finder as well:

Finders - Rigel QuikFinder Compact Reflex Sight

John

[themos]

There's a second hand RDF and a bracket to hold it on to your scope on sale right now, on SGL. ( http://stargazerslounge.com/sale/86850-rdf-various-brackets.html ) You'll have to sort out which bracket you need. Should cost about £15 plus a battery. Right angle correct image finders are a lot more expensive but then again they help with fainter objects. Your call.

[stev74]

Hi Lerxst,

Polar aligning for visual observing isn't that difficult. All you have to do is set your latitude on the latitude scale on your mount to whatever it is for where you live. If you dont now it just look up multi-map and put in your postcode here - Maps of the world, street map search - powered by Multimap

Then just point the leg of your mount that has the 'N' at the top north. You can do this by finding the star Polaris as it's very close to north. Remember it's the mount your aliging so you can do it before you attach the scope and counter weights. A good place to go for a simple guide is astro_babys website (a member on SGL) - Simple Polar Alignment for Beginners. There's also lots of other useful help on her site. I've really found her site invaluable I can polar align and do collimation because of it!! (thanks astro_baby!!)

I was also having similar problems with my 9x50 finder and couldn't find much until I bought a Rigel Quick Finder it uses red circles instead of a dot. There are bigger finders like the Telard or Sky Surfer V but for your scope I think the Rigel is a good size. I got mine from FLO - http://www.firstlightoptics.com/proddetail.php?prod=rigel_quikfinder. Remember you can get a discount for none Skywatcher products as your a member on SGL just give them a call. So you use the RDF to star hop from a known location to where you think a deep space object (DSO) is then fine tune using the 6x30. Personally I find the combination of the Rigel and the 9x50 better than a right-angled finder.

I'd also recommend buying The Sky At Night magazine it has lots of useful info on things to see in the month and star maps to help you find them.

Cheers

[TheThing]

Also, you might find M31 more easily by going out from Pegasus, rather than down from Cassiopeia. Have a look in Turn Left at Orion (borrow from your library if you don't have a copy) for pointers.

[brianb]

Also, you might find M31 more easily by going out from Pegasus, rather than down from Cassiopeia.

Yup.

You shouldn't need the finder until you're within a few degrees of the target, at which point being able to recognise constellations isn't an issue. Turning a chart upside down isn't much of an issue either. What IS an issue, to me, is that a right angle finder is really confusing - guessing a 90 degree angle to an accuracy of one or two degrees is not easy; try driving whilst staring out of the passenger door window if you don't believe me . With a straight through finder you're looking intuitively in the same direction as the target.

Red dot / Telrad finders are at least intuitive but don't help you to see things that are too faint for the naked eye.

A 8x50 finder will have a narrower field & show fainter objects than a 6x30, which is IMHO just too small.

But the best advice I can give is to learn to use your equatorial mount. It's a big help, if it's reasonably accurately set up and if you understand its movements and how they relate to star charts.

[TheThing]

NB - M31 can be a difficult target to find if you have any degree of Light Pollution. People say it is a naked eye object, but anywhere near a major town/city and it isn't (I have real difficulty getting it 18 miles out from London - see the observing reports section). It can be just a grey smudge that doesn't show up well in the finder scope!

[Lerxst]

Allright thank you for your help all! I just got off the phone with the good guys at FLO, and they recommended the Rigel Quick Finder - which is hereby ordered.

stev74: polar aligning is a bit difficult at the moment. I'm in Norway, and polaris is so high in the sky the alt on the EQ3-2 won't go that far....

TheThing: Yup, I got Turn Left At Orion. But thanks for the Pegasus tip. Weather's supposed to be splendid for a few days ahead so I'll definiately be out this evening trying to locate it.

Again, thanks all, I find these forums extremely good and full of friendly and helpfull people

[kniclander]

Yup.

guessing a 90 degree angle to an accuracy of one or two degrees is not easy; try driving whilst staring out of the passenger door window if you don't believe me . .

writing from my hospital bed, I would recommend a correct image finder if you are following star charts because you can use it to hop between stars that are too faint to see naked eye and after a while it gets really intuitive and you do it really well, ie you get a very good feel for magnitudes through the finder and distances.

a rdf is only good for knowing where you are pointing but after a while you get a very good instinct for that too.

[John]

The chart below shows the way I find M31 - The Andromeda Galaxy. Beta ( and Mu (u) are the key guide stars. Just put your red dot where the chart shows M31, pop your lowest power eyepiece in, pan about a little and the fuzzy core of M32 should hove into view.

As you can see - go the other way about the same amount from Beta and you can find M33 - it's much fainter although also a fairly large, face on, spiral galaxy - needs dark skies this one !.

John

[acey]

What you need most of all is a map. Lots of possibilities, online or in book form. I started out with the Cambridge Star Atlas which will certainly get you to M31.

You can find M31 from a light-polluted back garden quite easily with a 6x30 finder (that's how I first found it), as long as you have some way of knowing where you are, and where you're meant to be going. Just sweeping around and hoping you'll see it won't work.

Various books (such as Turn Left At Orion) explain the idea of star-hopping. You begin with a bright naked-eye star that you get in the finder. You compare this with your map, remembering that the map will probably need to be turned upside down. With practice you'll get the feel of how much space on the map the field of view of your finder takes up - one tip is to make a wire circle of that size, or draw one on transparent overlay.

An 8x50 finder will show you more stars and this will make things easier, as long as you can work out which stars you're seeing. That comes with practice.

I would agree that for light-polluted situations an 8x50 is preferable to 6x30, though for several years I used a 6x30 for all my finding, mainly at dark sites. And the one big thing I learned is that it's not the finder that counts, it's the map.

I soon found the Cambridge Star Atlas insufficient for finding deep-sky objects, and moved on to SkyAtlas 2000. This is the one I'd recommend, or failing that, the pocket-sized Peterson Field Guide to Stars and Planets.

[TheThing]

...or Sky and Telescope's Poket Star Atlas, which I have found to be invaluable (and pocket size too, if you have big pockets!)

[Lerxst]

Again, thank you for all the tips. I take back what I said about Polaris being too high in the sky, I just had a look at my scope (the wonders of being able to work from home at days!), and the alt can be tilted 90 degrees - that should make Polaris visible even if it's directly over head, right?

[stev74]

If your only doing visual observing you just need to point the tri-pod leg with the 'N' written on it north, roughly where you see polaris. Or use a compass to find north if it's easier. Remember it's not the scope you align it's the mount.

[ZOG]

Hi, it could simply be that you aren't using the finder correctly. First make sure it is aligned with the scope by lining up a distant object in daylight and making sure that the view in the finder is the same as that in the eyepiece.

When using the finder at night, don't try to see the whole constellation through it, the finder doesn't have a wide enough FOV. Find the W of Cassiopeia, pick a single star, (the bottom star of the right hand V is ideal) and line it up in your finder KEEPING BOTH EYES OPEN, this makes things so much easier and applies to your Quickfinder as well. Once you have that star in the EP, starhopping to Andromeda is fairly easy.

[Lerxst]

If your only doing visual observing you just need to point the tri-pod leg with the 'N' written on it north, roughly where you see polaris. Or use a compass to find north if it's easier. Remember it's not the scope you align it's the mount.

Yes, according to Multimap, my lat is 59:56. I've adjusted the mount accordingly so it should all be ready for when somebody turns off the sun.

Zog, that was a great idea about keeping both eyes open, I'll be sure to try that one tonight.

[acey]

that should make Polaris visible even if it's directly over head, right?

If Polaris is directly overhead then you're standing at the Earth's North Pole. At that location, any alt-az mount is automatically an equatorial.

If your latitude is 60 degrees then Polaris looks to be 60 degrees above your horizon, and it stays there. You point your polar axis towards it, then your mount will behave as an alt-az would at the Earth's North Pole, if you get my drift.

This link might help:

Polar Alignment of your Equatorial Mount - McWiki

[Lerxst]

Just a heads up; I was out last night again, this time after actually reading McWiki's tutorials, not just skimming them, and I feel kind of embarrassed because I had my scope perfectly polar aligned within one minute, and I also double-checked the finder scope alignment with Polaris so I knew it was spot on.

Before I posted the thread yesterday, I had a vague idea of how the equatorial mount operates, but since it was not lat adjusted properly, I always had to fiddle with both the DEC and RA knobs in order to track about anything, and the scope always moved in random, weird directions. But after setting the lat to 59 and polar align it, I had a perfect track of Jupiter with only small adjustments with the RA knob for as long as I was out.

Didn't find M31 though, but when checking Stellarium when I got back in, I saw that it was way further south from where I thought it was and where I was looking, so I will definiately try to locate it tonight.

And again, thanks for the help, you all are the main reason I was finally able to operate the mount and navigate the skies for the first time successfully.

[TheThing]

Good news! Cracking the polar alignment is a big step and it will get intuative as you go on. When I started out, I just plonked my scope wherever and moved it around to see stuff. When I finally learnt to polar align weeks later, it was much easier.

Keep trying at M31 and good luck! Let us know how you get on.

[Lerxst]

I found M31 yesterday on my first try, going from Pegasus. Thanks for that tip!

It was just a faint fuzzy in my scope, but then again it wasn't completely dark and it was only about 21:40 CET (it's still fairly bright outside at these lattitudes).

However, I have to questions:

1. Will a filter (not color filter) as a nebula filter or OIII filter or something show more details, or are thy only useful when doing astrophotography?

2. I seem to be coming down with a case of aperture flu - from my 6" 1200mm, how high in aperture do I need to go to see some details?

[brianb]

from my 6" 1200mm, how high in aperture do I need to go to see some details?

M31 is HUGE, you need to get a field of view of 4 to 5 degrees to do it full justice. A very low power on a small refractor is good, or large binoculars. Because of the large size - entialing a short focal length - M31 is one of the relatively few deep sky objects which does not benefit from an increase in aperture over about 3": you will see further into the core but the outer arms will be lost in a 6" scope.

You do need a dark, transparent sky to do it justice. In this respect it's the same as other galaxies - even our own - if you can't see the Milky Way well, you're going to struggle with the outer portions of galaxies.

[acey]

1. Will a filter (not color filter) as a nebula filter or OIII filter or something show more details, or are thy only useful when doing astrophotography?

2. I seem to be coming down with a case of aperture flu - from my 6" 1200mm, how high in aperture do I need to go to see some details?

With small apertures a filter will have no effect, other than to make the galaxy fainter.

As for seeing details, it depends what you mean by details. With binoculars you can see the core, halo, and can infer the dust lane. With larger aperture you only see a small part of the galaxy in the field of view, but you can look for details such as the galaxy's globular clusters (which look like stars of mag 15 and fainter), the star-cloud NGC 206 on the southern tip, and star-forming HII regions (which might be enhanced by a nebula filter), etc.

Most important thing, as has been said, is to see it in the darkest sky you can. Also to look as carefully as you can, as none of the details pop out like a photograph.