Author Topic: What is a good way to star hop ?  (Read 961 times)

Brian Olatunji

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Re: What is a good way to star hop ?
« Reply #15 on: January 11, 2018, 12:53:59 PM »
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Finally, I'd like to add that if you are using paper star atlases like the S&T Pocket Sky atlas, it helps to have a reference for the angle of the field of view to put on the page. This can be a circular template, a loop of wire, or even a coin that that closely matches your Telrad, or finder, or low power eyepiece field of view.
On the original PSA the 4ยบ Telrad circle is the same size as a penny on the charts. For the new "Jumbo Shrimp" as many are calling the Jumbo Pocket Sky Atlas, a quarter works. Even loops of wire that look like magnifying glasses (without a lens) can help you with your sense of scale of the field of view your equipment.

Great tip ! I will certainly use it. Thank you.

smalmonica

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Re: What is a good way to star hop ?
« Reply #16 on: January 12, 2018, 02:17:56 AM »
With equatorial mounts and a 'reasonably' decent polar alignment you can use RA or the Dec drift methods. Example of RA drift method, the open cluster M67 in cancer has a declination of plus 12 degrees, The bright star Regulus has a declination of12.13 degrees. By putting Regulus in the center of the field of view in your telescope( wide field eyepiece) and locking the dec axis you can now slowly move the scope in RA about 1 hour and 20 minutes west to get to M67.

The dec drift method works the same way except now you need to find a bright star that has approximately thesame RA as the object you are looking for. Example M41 the open cluster in Canis Major has an RA of 6 hr and 45 minutes, The bright star Sirius has an RA of 6hr and 43 minutes. By placing the star Sirius in your telescope FOV and then locking the RA axis you can pan south in dec to arrive at M41.

These are two easy ones but there are many more. Using a telrad is a great aide with these methods as it allows you to accurately offset from your 'finder' star up to 3 degrees. As you become more familiar with the sky you will be able to use fainter and fainter 'finder' stars.

Derek Vail

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Re: What is a good way to star hop ?
« Reply #17 on: January 15, 2018, 03:33:45 PM »
I have found the EQ mount that came with my Powerseeker to be a pain. I have ended up using it like an alt-az mount (tip from another amateur astronomer). Which is why I want to go to a Dobsonian soon. Just easier to move around and learn without dealing with setting circles, polar alignment, etc.

Robert Cavalli

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Re: What is a good way to star hop ?
« Reply #18 on: January 15, 2018, 06:10:47 PM »
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I have found the EQ mount that came with my Powerseeker to be a pain. I have ended up using it like an alt-az mount (tip from another amateur astronomer). Which is why I want to go to a Dobsonian soon. Just easier to move around and learn without dealing with setting circles, polar alignment, etc.

My sentiments exactly regarding GEMs.

To answer your question regarding which finder, there's nothing wrong with this one...

http://agenaastro.co...age-finder.html

Marcus Kucrud

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Re: What is a good way to star hop ?
« Reply #19 on: January 18, 2018, 01:56:58 AM »
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I have found the EQ mount that came with my Powerseeker to be a pain. I have ended up using it like an alt-az mount (tip from another amateur astronomer). Which is why I want to go to a Dobsonian soon. Just easier to move around and learn without dealing with setting circles, polar alignment, etc.either but with EQ mounts you can generally just plop the thing down with the mount oriented toward the north star, and it helps with star hopping because when you move the telescope in altitude you're going very close to north and south, or in azimuth you're going east and west. I've found it easier to starhop like that

One thing about EQ mounts though, you don't need the setting circles at all if starhopping. If you have the EQ mount angled equal to your latitude and simply point the mount toward the north star, you are polar aligned enough to have it help you starhop. That is, after doing that, moving the scope in one axis moves your scope exactly north or south (or close to it), and the other axis exactly east and west. That makes it easier to look at your star charts and find a bright star, say, 4 degree north of the current field of view, and then move 2 degrees to the right or left to get to the object, or another bright star, etc. That's how I starhop, though usually I'm using a fork mount on a wedge, same concept though. Also if the EQ mount has tracking, it will keep your current field of view while you look at your star charts, instead of drifting.

inovilmei

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Re: What is a good way to star hop ?
« Reply #20 on: January 18, 2018, 04:30:37 AM »
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To answer your question regarding which finder, there's nothing wrong with this one...

http://agenaastro.co...age-finder.html
+1

That's exactly what I have and I love it. It's handy for looking at extended objects like the Pleiadeswith alone as well. I often go from binoculars to the very similar view in that particular finder before commencing star hopping.

EDIT--That reminds me, I strongly recommend a finder of at least 50 mm aperture, especially for finding the fainter objects in moderately light polluted skies. That particular one offers just over 5 degrees field of view, which can just take in both the pointer stars of Ursa Major. Those stars are 5 degrees 22 minutes apart and are a good reference for verifying a five degree field of view, which should just fit between them without showing either one. That particular finder, with an angular field of just over 5 degrees, covers the same amount of sky as a U.S. Quarter does on the pages of a Pocket Sky atlas.

riaherrvodo

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Re: What is a good way to star hop ?
« Reply #21 on: January 18, 2018, 05:11:43 AM »
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Quote

To answer your question regarding which finder, there's nothing wrong with this one...

http://agenaastro.co...age-finder.html
+1

That's exactly what I have and I love it. It's handy for looking at extended objects like the Pleiadeswith alone as well. I often go from binoculars to the very similar view in that particular finder before commencing star hopping.
Yea I have similar finders on both of my larger scopes and they're very useful. Under even decent skies you can see a lot of DSOs right in the finder, then you just have to move the scope to centerthe objectin the finder and you're there.

Aaron Maggot

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Re: What is a good way to star hop ?
« Reply #22 on: January 20, 2018, 11:29:35 PM »
This is awesome guys ! Thanks for all the great tips and pointers.

telschronexic

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Re: What is a good way to star hop ?
« Reply #23 on: January 21, 2018, 03:49:46 AM »
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The 8 inch Skywatcher Tube Dob comes with a straight-through finder and a single speed Crayford focuser. I used straight-through finders for many years but recently switched over to RACI finders.. Straight through finders have some advantages but the rotated image and the more awkward viewing positions are serious disadvantages. Starting out, the comfort and ease of translating between charts and the finder scope make the RACI the better choice.

If you figure an RACI finder costs about $75, and then the Z-8 comes with a 30mm 2 inch finder eyepiece and a nice two speed focuser, I think the Z-8 is a better value, you get more for your money...

Regarding Star hopping:

Charts:

I have been using electronic charts out in the field for about 15 years. These days I use Sky Safari 4 Pro.. (5 for the iOs). Compared to using paper charts, it does seem like cheating.. I get the correct view of the sky for my location and time. The screen can show me what I want, if I want magnitude 5 stars, magnitude 7 DSOs and 25 degree Field of view.. I have it. IF I want magnitude 10 stars, DSOs to 13th magnitude and a 15 degree TFoV, I have it. The databases are far larger than is possible with a paper chart, not only are they much deeper but the information provided for each object is much greater. I can do searches and build observing lists right there in the field. The observing list can circle the objects on the screen..  I have Telrad circles right there on the charts.

Binoculars, Red Dot/Telrads, RACI finders plus a low power wide field eyepiece are all physical parts of the tool kit. They all have their place.. If the skies are dark, I can find most objects with just a Telrad. And that can be with a scope whose field of view is barely larger than the moon..

Jon

aththrilnalo

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Re: What is a good way to star hop ?
« Reply #24 on: January 22, 2018, 08:02:11 PM »
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Thanks, guys. Great tips and encouragement.

Question about the RACI and Telrad finders...

I plan to get at least an 8" dob that comes with (I think) a 9 x 50 finderscope. Was thinking of a Z8, but might go with a Sky Watcher to get the discount from being a member of the forum. Anyway, is that finderscope adequate for me for now, or should I plan to go to a Telrad or RACI right away ? I know there are different opinions on this, but I am open to all of them of course.


I have both a RACI and telrad on my 10" dob. I've found that, for me, using the telrad to get to the nearest bright star, then the RACI to slowly hop to the target works best. Depending on what I'm looking for, I may then move to a low power EP to get the final way to the target. Once there, you can change EPs to give you the view you want.

Regarding your original post on star hopping with a refractor, I've found that when using a tripod mounted manual EQ or Alt/Az mount, I actually prefer a straight through finder for star hopping. It makes it easier for me to look over the finder (like a gun sight) to manually move the scope to get me to my starting bright star and then use the finder to hop; your head stays in the same position, and your eye only has to move slightly between the two until you find your bright star to start the hop. The only difficulty with this is the finder has a N/S inverted image, but when I move to the EP in a diagonal, the image is inverted E/W. Normally, this isn't a problem unless I can't find the object and move between the finder and EP. I have to stop to think about which direction I need to move.

veworltonuc

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Re: What is a good way to star hop ?
« Reply #25 on: January 23, 2018, 01:26:50 AM »
Thanks again, guys ! Lots of great information for me to soak in. But I can keep coming back to this thread down the road to try different things out.

galpaydabta

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Re: What is a good way to star hop ?
« Reply #26 on: January 23, 2018, 02:12:43 AM »
There are many different ways to star hop. (Some will mis-type "star hope" or "star hoping" by ironic accident.) Getting lost along an extended hop can lead one to guessing and hoping and usually requires a restart at the last place that you KNEW was right.

The type of star hop you choose will often be determined by your comfort level with the type of target, its dimness, or the amount of stars bright enough to help you along the way. (When tackling the Virgo Cluster of galaxies, most hoppers have to use brighter galaxies instead of stars.) The amount of light pollution you have to deal with will often determine your choice of optical finder or Telrad-like device, with optical finders being more useful in light polluted viewing.

My number one way to get to targets is to use triangles or other simple shapes. My number one atlas is the Pocket Sky Atlas. Its dimmest stars show up in my 50mm finder. I will stare at the correctly-oriented chart to put an isosceles (or whatever) triangle of a particular sharpness and orientation into my short-term memory. Typically, two stars serve as the anchors at the base of the triangle and the target is at the sharpest vertex. This is one way to find M-101 above the Big Dipper's handle.

When I've successfully found a new target that was a challenge, I will record the star hop method that worked for me.

Good luck.

paurustmorba

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Re: What is a good way to star hop ?
« Reply #27 on: January 26, 2018, 12:33:28 AM »
My primary method is to put a lower power EP in and get the area in question in the telrad. If it isn't an object I already know how to locate, I use a combination of the S&T Pocket Atlas and SkySafari to educate myself on the reference stars to get on target. I usually have the object in the field of view the first time I look, and there is rarely any "hopping" needed. Really faint stuff might require a few adjustments and nudges, but more often than not, I can get my dob on target this way before the computerized/motorized folks are on target. I have never had much use for a RACI, but it might be because I have nice dark skies to work with and can more easily find stuff using both eyes and a telrad. For that reason my RACI has been in the box for a couple of years now.

I can usually do the same thing with my refractor and a red dot sight on an equatorial mount (not motorized), but I am touch slower than I am with my dob.

Kunjan Blanco

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Re: What is a good way to star hop ?
« Reply #28 on: January 31, 2018, 12:23:21 AM »
I'm going to see how the finder scope works for me on the Z8 (I know, I keep vacillating between the Z8 and other dobs). But these are all great sounding techniques, I can't wait to eventually get the scope and try out these ideas ! Thanks !

Chad Fithian

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Re: What is a good way to star hop ?
« Reply #29 on: January 31, 2018, 02:57:44 AM »
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There are many different ways to star hop. (Some will mis-type "star hope" or "star hoping" by ironic accident.) Getting lost along an extended hop can lead one to guessing and hoping and usually requires a restart at the last place that you KNEW was right.

The type of star hop you choose will often be determined by your comfort level with the type of target, its dimness, or the amount of stars bright enough to help you along the way. (When tackling the Virgo Cluster of galaxies, most hoppers have to use brighter galaxies instead of stars.) The amount of light pollution you have to deal with will often determine your choice of optical finder or Telrad-like device, with optical finders being more useful in light polluted viewing.

My number one way to get to targets is to use triangles or other simple shapes. My number one atlas is the Pocket Sky Atlas. Its dimmest stars show up in my 50mm finder. I will stare at the correctly-oriented chart to put an isosceles (or whatever) triangle of a particular sharpness and orientation into my short-term memory. Typically, two stars serve as the anchors at the base of the triangle and the target is at the sharpest vertex. This is one way to find M-101 above the Big Dipper's handle.

When I've successfully found a new target that was a challenge, I will record the star hop method that worked for me.

Good luck.

Lines and triangles are also the primary way that I star-hop ("the galaxy is about 1/3 of the way between naked-eye star X and naked-eye star Y", or "the cluster makes a flat isosceles triangle with X and Y"). This usually is enough to get my target within a 1-degree eyepiece field, if that's what I'm using. Find the field-of-view of your eyepieces by putting their stats (and those of your telescope) into this:

http://www.davidpaulgreen.com/tec.html

I used to use a finder eyepiece with a 1-degree field; I've gotten lazy, though (and a bit better at star-hopping), and use my primary eyepiece for both (112x, 42' field). If my target is small or faint or both, I also use the TriAtlas app for iPhone/iPad to pinpoint the right position; the app has stars down to magnitude 13, and acts as a paper atlas. With this eyepiece and the app, I was able to sweep up all of the NGC globular clusters in the M19/Pipe Nebula region and the planetary nebula NGC 6369 without having to use a Telrad or finder or take my eye away from the eyepiece--it was just a matter of hopping from one globular to the other, using the stars plotted in the app.