Nicely done! Should be required viewing for the first time telescope owners this holiday season.

@JenhamsAstro

6 жыл бұрын

Thanks Garry.

@devonhc7770

4 жыл бұрын

@@JenhamsAstro me!

Glad I found this video. Excellent! I know exactly what I need to get for terrestrial use of my telescope. Thanks so much Graham!

@JenhamsAstro

2 ай бұрын

Glad it was helpful Darren.

Thanks for the refresher on telescope images. I'm dusting off my Celestron 6SE for a little stargazing with my grands and wanted to be prepared for the inevitable questions that are sure to come up.

Thanks for this informative video. These simple transformations usually become a bit confusing when we are trying to relate the observed features - especially while using a Dobsonian. I was facing similar issues while mapping my images of Mars with NASA's charts.

Thank you for your excellent information. Informative yet simply presented. You helped me really get back into the hobby of astronomy. Great job!

That was a very helpful demo thanks. I have just purchased the Celestron Astro Fi 5 inch SCT scope. I noticed whilst calibrating the finder scope that the left/right was flipped, thus text looked back to front! I don't think I will get a star diagonal for now as I hope to use it for astro visuals and astro imaging with my DSLR.

I Literally Just Got The 2” Williams Optic Dura Bright For My 6”..And Found a Fun Little 5mp Wifi Camera..Pretty Decent Actually,I Was a Little Impressed For $50 On Ebay,lol..But Making Sure It Works,Going To Give It To My 15 Y/O Great Niece With Her 1st Telescope,Probably Going With The C-90..Love Mine Although I Havent Had It Out Lately,As I Got The Eqm35 Pro The Other Day For My Birthday,lol..Playing..Learning..Its a Whole New Ball Game..Great Video For Explaining..Happy Days and Clear Skies❤️🔭❤️

@JenhamsAstro

3 жыл бұрын

Thanks! Clear skies to you as well (hopefully with Perseids!)

Hi, thanks for the video! Got a new C90 and I am learning. I wanna get a 90 deg diagonal. So you show here the Celestron prism 90 deg diagonal. What happens if you use a mirror diagonal? I guess the result is the same , right? So what's the difference of a prism diagonal (like a celestron for $35) versus a mirror one (for $80 to 100) ? I guess the mirror is better because it reflects more % of the light. But are there other factors to consider for a telecope like a C90 where a prism would be better than mirror or the other way around? Thank you!

@JenhamsAstro

6 жыл бұрын

Hello, you are right that the image orientation (right way up) and left to right inversion will be the same with mirror or prism. Generally very cheap diagonals of either variety may not be of the best quality or consistency, and some can even degrade image quality. Mirror vs prism... If you had a faster scope like an apo refractor then some say that a prism may introduce some false colour vs a mirror. This seems plausible, but whether or not it is actually true is academic with a longer focal ratio scope like the C90. As for mirrors then some manufacturers make a big deal of their coatings transmission percentage and of the longevity of this reflectivity. Personally I am not sure I can tell the difference between 97% and 995, but it does seem reasonable that the achieved transmission could be higher than with a prism. Mirrors are more "in fashion" these days with a lot of choice. Assuming you don't buy a defective unit that has introduces optical imperfections then at the higher price point you tend to get genuinely useful features like a brass compression ring to grip your eyepiece, vs a couple of screws on a cheaper unit. A cheap diagonal may not be blackened properly leading to stray light. Other (more expensive..) units offer locking mechanisms to further secure your EP. This can be a big issue with some heavy EPs especially 2" units. I think a $80-100 mirror unit will feel like a big step up from a cheap plastic prism unit. I am a big believer in reading reviews and forums for advise on a specific product e.g. Orion vs WO vs Skywatcher. I hope this is of some use. Graham

Very good!! But now I was a little confused! I just bought (it still didn't come to my hands), the William Optics Redcat 51mm Petzval Apo Refractor, I'm going to use it with my reflex for astrophotography, but I saw photos and videos of land, birds, made with it, and I was wondering what it would be like the right configuration, just to avoid the inverted image. So what should I get to use the telescope + the camera for nature photography or video? I hope you can get me this doubt !! Thank you!!

@JenhamsAstro

4 жыл бұрын

Adriana Amez Hello Adriana, I am very jealous! Looking at the following review suggests that WO offer an erecting diagonal for the Redcat. astrobackyard.com/william-optics-redcat-51/ please let me know what you think of it. Clear skies, Graham

I've heard prism diagonals can give better contrast for planet viewing. Is there any through tho this? BTW they have 90 degree prism diagonals too.

@JenhamsAstro

4 жыл бұрын

PublicCommerce Hello, personally I use 90 mirror diagonals these days, which have high reflectivity, and I’m not sure if I have noticed any inferior contrast vs a 90 degree prism. But bear in mind under my skies I spend more time videoing the planets straight through than visual observation with a diagonal of any sort, so maybe a dedicated visual observer may have a different view.

Hi Graham, i realise that a prism affects the view for astro - but is this more at high power? I'm wanting to take correctly oriented sketches of star patterns at around x16 and x26...Thanks..

@JenhamsAstro

4 жыл бұрын

Hi, it's true that the spike effect and other image degradations are a bigger problem at high magnifications, and renders erecting prisms useless for, say, splitting a close double star. If you think you might want to go to higher powers I'd rule out a 45 prism. For low powers it could be OK.

Hi, i want to make my reflector telescope use as terrestrial viewing, can i use the 45° diagonal prism as i want to make the view not inverted?

@JenhamsAstro

6 жыл бұрын

Haydar Sanada Hi, normally a Newtonian type of scope will not allow you to achieve a focus using a diagonal. The extra light path of the diagonal means that you need to “focus in” by an equivalent distance to focus the image. Normally you reach the end of focuser travel first, unless you fit a low profile focuser. Refractors and SCTs / MCTs allow more travel and hence can use diagonals.

Hi, is the C90 a good scope for upgrading from cameras fro astrophotography? If no,then could you suggest a scope that could act as an intermediary. Also how are the nebulae /star clusters captured using the C90 and a dslr?

@JenhamsAstro

2 жыл бұрын

Hi, I suggest that you don't start with a C90 unless you only want to photograph the moon, small bright DSOs and brighter planets- its aperture, long focal length and small field of view are not ideal for faint targets like nebulae. For a budget/intro option you could try something like an 80mm f/5 achro like the "ST80" scope. It will have some false colour but its fast and it's short focal ratio is forgiving. If you go upmarket a bit you could try a 150mm f/5 newtonian, or a small apo like an 72ED. All AP options require a tracking mount. You will soon find that the camera is at least as important as the aperture, and that a fast focal ratio is a must! I hope this helps as there are many options.

I have a 575mm F6 scope that has trouble with IN FOCUS using 2" mirror diagonals. Will a 2" prism diagonal help with in focus? Thanks

@JenhamsAstro

Жыл бұрын

Yes it might if you currently can’t rack the focuser far enough in.

I haven't had a chance to look through any other telescope than a big monster 10" dobsonian I inherited, that is a real bear to carry out of the house for viewing. I see many KZread videos where people have small scopes on a tripod like this video which seems very appealing for convenience of moving. Having only ever looked through one telescope, I'm not sure what I would be giving up by going with a smaller tripod mounted scope...if anything. For those who have used both...is there any advantages of the monster dobsonian that I would miss? I see people post pictures that look just as good, if not better, than what I see from this huge thing....from much smaller scopes.

@JenhamsAstro

2 жыл бұрын

The visual experience of many faint objects is significantly better in a larger scope than with a small grab-and-go setup. The difference exists with planetary viewing as well but in my experience it’s less obvious as the objects are bright. Nothing looks the same as an astrophograph when the same target is viewed with your eyes. Small scopes can produce great photos using long exposures and multiple images, but often you can hardly see an object like a nebula visually at all with a small scope, even if the object looks impressive in a composite image made from an hour of light gathering. But the best scope is the one you use, and portable small scopes can become the most used and give great satisfaction as long as your adjust your expectations to suit.

@PowerScissor

2 жыл бұрын

@@JenhamsAstro Thanks for the info!

spotting scope is already producing a proper image. is it correct? why should this corrective apparatus

@JenhamsAstro

5 жыл бұрын

enix hello yes the 45 degree prism supplied with the C90 is turning the inverted image back to be upright. If you didn’t use the prism and put an eyepiece directly into the back of the scope the image would be inverted.

@nx7640

5 жыл бұрын

@@JenhamsAstro thanx. I have a question. celestron with 8-24 mm eyepiece. How many X zoom range can I reach with c 90

@JenhamsAstro

5 жыл бұрын

enix the zoom eyepiece will give a magnification between about 50 and 150x

@nx7640

5 жыл бұрын

@@JenhamsAstro thank you