Bushnell 675x60 Deep Space Refractor

[kngavl]

I have this telescope, and I'm having trouble seeing Dso's or anything on that matter, is it normal to not be able to see anything the first days, I mean I saw the moon, some stars Venus Mars and such but when I went to see M82/81 I couldn't see a thing and I was positive I was right on it. I have oly the stock components none other. Oh and how do you do the polar alignment, when ever it says set the elevation to like 90 my telescope is pointing straight up but when I set to 49 (my latitude) it works fine, and one more thing I don't understand how to use RA at all, do I point at polaris and then adjust my ra setting thing to 2/30 hours and if so which one do I use,<br />Ra goes 1 2 3 4 5 6 7 8 9 and so on, but theres another thing underneath that goes opposite so<br />It looks like this<br />1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21...<br /> 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ...<br />So do I use the upper value or the lower value?<br />If you could help me that would be great, i've had this telescope for a year now so I would like to start using it now <img src="/images/icons/smile.gif" />.<br />Thank you for your time.<br /><br /><br />Telescope Stats below.<br />Focal Lenghth: 900(mm) <br /> <br />Eyepieces: 4mm, 12mm, 20mm <br /> <br />Magnifications: 45, 75, 135, 225, 675 <br /> <br />Great for: Night Sky and Land-Based Viewing, Experienced Astronomers <br /> <br />

 

[tfwthom]

Experienced Astronomers ????????<br /><br />I love that one......like any experienced astronomers would have one of these scopes! In a way they are right, you have to be an experienced astronomer to even use one because you have played around with enough "toy" telescopes to know all the tricks to getting one of these to work. (any telescope that brings up "power" is a "toy" sold to people that don't know anything about telescopes)<br /><br />First forget about the numbers (setting circles) just star hop. They put the numbers there just to make the scope look like its the real thing.<br /><br />Second you are going to be lucky to see any DSO's stick with the Moon and planets. Because it's a refractor and thats what refractors are for anyway. (other then bright DSO's 60mm doesn't gather enough light)<br /><br />Things to check....is the mount stable? If not try extra weight (a milk jug filled with water or sand tied to the center of the tripod works) Is the finder scope aligned to the main tube? Align the finder (pick the top of a telephone pole in daylight and align them)<br /><br />Find your local astronomy club and go out observing with them. I always try to help the people that bought these types of scopes if they show up at star parties. Besides it gives them a chance to look through the better scopes.<br /> <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>

 

[kngavl]

Thanks, my mount is very stable it doesn't move at all.<br />What a better surface for the mount, grass or a harder surface like wood(With slight carpet over it)?<br />I can't seem to align my finderscope, during the day it is unbelivably hard to do so, when ever I tighten the screws the finderscope will always move away from where it was and when I did do it at night it was still off.<br />I was trying to see M82/M81 and by my claculations I was looking at the other galaxy in that area NGC 3077, I knew it was rihgt there because there is a set of 3 stars that almost surround it (They more point to it). I can't see M31 because of my location is blocked.<br />Oh and I did use my settings Lat/Dec to find stars, I could find any star with these settings on the telescope. The only thing I didn't understand was the RA but I would put in the position of the star as a latitude then find the general area and it would always be in my scope, just couldn't find the M82 because I can't see a thing there. I don't have much light polution here either, (small town.) Basicly what I can see form my house is the big dipper, casseopia, little dipper and that general area to my North.<br />Thanks again.

 

[kngavl]

Just one more thing sorry, yesterday I think I saw M31. It was a odd hazy patch of light, nothing spectacular or really interesting but it was there. The only thing was I was using cartes du ciel to find it but on cartes du ciel it showed the bottom of andromeda(Constilation) with a bright star then above it another and then a path to another far away and M31 was on this line so I looked on the line and found a little hazy patch of light, but instead of being more to the left of the line as pointed out in Cartes du Ciel it was completely to the right so I scanned the area and that thing was the only interesting object in the region. This was Andromeda or not? <br />This was in my 8 x 30 binoc's, I had to stand on a picknick table to see over my house.

 

[kngavl]

How do you tell the magnification of binoculars? Like as you said my telescope could go to 135x I have 8x 30 binoculars, so would that mean I have a magnification of 240?

 

[tfwthom]

Magnification is 8<br /><br />The 30 is the objective size.<br /><br />10x50 means 10 power 50mm objective lens <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>

 

[kngavl]

Sorry about this, but how would that be considered with the 135x, so this would be 8x? And do you know of any tables that show like what the eyes limits are for magnification and a binoculars limits small telescope, ex: The eye can see to 1.98 (visual magnitude).<br />Thank you again, these boards are so helpfull.

 

[tfwthom]

MAGNIFICATION: BY FOCAL LENGTHS<br />M = F/f<br /><br />where M is the magnification<br />F is the focal length of the objective<br />f is the focal length of the ocular<br /><br />At prime focus (ground glass), magnification is 1x for<br />each 25 mm of F<br /><br />APERTURE<br />D = F/f<br /><br />where d is the aperture of the objective<br />F is the focal length of the objective<br />f is the f-number (f/) of the objective<br /><br />MAGNIFICATION: BY FIELDS<br />M = Alpha/Theta<br /><br />where M is the magnification<br />Alpha is the apparent field<br />Theta is the true field<br /><br />Apparent Field: the closest separation eye can see is 4', more<br />practically 8-25', 1-2' for good eyes. The Zeta Ursae Majoris<br />double (Mizar/Alcor) is 11.75'; Epsilon Lyrae is 3'.<br /><br />True Field (in °) = 0.25 * time * cos of the declination<br />(in ') = 15 * time * cos of the declination<br />where time is the time to cross the ocular<br />field in minutes<br />A star therefore moves westward at the following rates:<br />15° /h (1.25°/5 min) at 0° declination<br />13° /h (1.08°/5 min) at 30° declination<br />7.5°/h (0.63°/5 min) at 60° declination.<br /><br />MAGNIFICATION: BY DIAMETER AND EXIT PUPIL<br />M = D/d<br /><br />where M is the magnification<br />D is the diameter of the objective<br />d is the exit pupil (5-6 mm is best; 7 mm may not<br />produce a sharp outer image)<br /><br />The scotopic (dark-adapted) aperture of the human pupil is<br />typically 6 (theoretically 7, 5 if over age 50) mm. Since the<br />human pupil has a focal length of 17 mm, it is f/2.4 and yields<br />0.17 per mm of aperture. 2.5 mm is the photopic (light-adapted)<br />diameter of the eye.<br /><br />EXIT PUPIL<br />d = f/f-number<br /><br />(by substituting F/f for M)<br />where d is the exit pupil<br />f is the focal length of the ocular<br />f-number is the f-number (f/) of the objective<br /><br />By substituting d=7 (the scotopic aperture of the human pupil)<br />and multiplying it by the f-number, the longest useful focal<br />len <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>