REVIEW: Celestron Firstscope PART 2 - How To Make The View Sharper
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- Опубликовано: 18 дек 2023
- This is the second half of my review of the Celestron Firstscope. I show how to collimate it and how to use masks to make the view perfect. Is this THE BEST starter telescope for kids? For the price, it just might be...
#celestron #firstscope #dobsonian
//VIDEO PART ONE REVIEW of Celestron FirstScope: • REVIEW: Celestron Firs...
//3D Part Files:
Mask Set: www.thingiverse.com/thing:483...
Eyepiece Holder: www.thingiverse.com/thing:127...
/// AMAZON AFFILIATE LINKS (Note: I earn a small commission from these links) ///
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SVBony Laser Collimation tool with adapter: amzn.to/3M9YOZz
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Best Value Set Of Upgraded Eyepieces: amzn.to/3Y7MYmn
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RUclips NOTES:
1) This video complies with the RUclips Community Guidelines and Terms of Service.
2) Soundtracks used with permission from my video editing suite, Camtasia
3) All products shown were purchased by my family with our own money.
4) Vine Boom sound effect used under paid license from Bluezone Corporation!
5) This video does not contain any controversial subjects, children, offensive material or language.
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Развлечения
This is a very interesting experiment, John. I've used an aperture mask on my 102 mm refractor to look at the moon and Jupiter (it changes the scope from an f/6.5 to about an f/12 and it helps greatly).
It was very interesting to see how the different masks affect the image; it was noticeable on video. Good stuff. Thanks!
Thank you for watching - I appreciate the feedback. This is one of those effects that is really neat to see firsthand.
That how I collimated mine, one screw, the ol' wiggle-jiggle, then taped it. Can't wait to try a mask.
Frankly, I didn't know of any other way to collimate it. Thankfully I used the right screw and could pivot from there.
According to equation I found at CN the F/6 i.e. 50mm aperture for 300mm FL gives 1/5 lambda - same as typical 114/900 spherical mirror scope that considered good.
Nice results - but really I think the eyepiece is part of the problem. You can test it with simple eyepiece camera
Agreed. The cheap ancient eyepiece design is not helping the situation.
@@reflactor On that topic, what's a decent eyepiece camera you might recommend? I made that cardboard mask, worked pretty good!
Thanks for this info John! I made a cardboard mask in a fashion as described in Part 1 of this review and it has certainly worked well with bright objects such as the moon. I have a Cometron variant Firstscope and it removed the colour fringing around the edge of tonight's moon from the supplied Kellners once the mask was applied. I even tried it with my 12.5mm Plossl and it also made a difference with this EP! The spherical mirror really throws things out but the mask makes quite a difference, although the brightness certainly diminishes significantly.
First of all, is this THE Danny Mok that I used to do speech contests with? Even if not, how are you? I was also surprised at how effective the masks were on these little Dobsonians. But I guess that's why somebody went to all the trouble to post them on Thingaverse (I'm glad they did). The tradeoff is that it does reduce brightness, but with the Moon and Jupiter, they're so bright that they are hardly affected.
@@reflactor hahaha, well if you'd lived in Australia at some stage in your life, we might have duked it out verbally, but most likely I'm not the Dan that you're thinking of! Love your astronomy vids as I only bought my first telescope when I turned 50 a couple of years ago and certainly appreciate all the info you present here. Unfortunately I don't have access to a 3D printer, which is why I went with cardboard!
Celestron xcell lx series eyepieces works wonders with this mirror. Especially 7mm it’s super sharp edge to edge. This series works very well with fast mirrors I totally recommend it for this telescope.
Month ago I was surprised seeing clearly 2 belts on Jupiter with lx 5mm eyepiece through 2x Barlow. Very sharp although focusing was a little tricky. Micro focuser would be another nice improvement. I love this little scope, soo portable.
I completely agree. If you put in a high quality eyepiece, this telescope will show you a solid glimpse of Jupiter with a hint of the two main cloud bands. A similar thing happens when I use my Explore Scientific eyepieces on it.
I miraculously somehow got Jupiter into view with my Celestron 70mm Travel Scope with its faux tripod. I was using Svbony 2x Barlow and Svbony`s cheapest 10mm Plossl. I saw two bands too but the moons were way too bright and didn`t impress. I remember much better images with a much longer 70mm refractor I paid 250 for in the mid 90s. But it was stolen. It had a wonderful tripod too. I could really zoom in on the moon with it and it was a great birdwatching scope too. I could find the hummingbird`s favorite perch and write down the equatorial numbers for it and the feeder and quickly move between them. It magnified hummingbirds to the size of condors. I could see great details and colors in their feathers like HD. I could read the numbers on a small digital display at a car wash and the name tags of employees inside a chicken place way down the road and almost read an electric meter on an old building 1/3rd mile away. I had a great telescope in the mid 1970s too that vanished.
John, that was one of the most interesting videos I've seen in quite a while. Really interesting results.
Thanks! I had a lot of fun experimenting with the masks. I'll probably make a bigger video about the offset masks specifically.
Great video. Very informative
Thanks for watching!
cool vid John & i like those ep holders. The F7 was the best one
Thanks! I agree. F6 was pretty close, but it still had some blurry areas.
I still don’t like these scopes LOL but one other upgrade is to create a mounting block underneath with a socket, so you can mount it in a sturdy tripod at chest level.
I also found that adding a 2x Barlow helps, as it effectively makes the mirror f/8. Does that make any sense.
I’ll have to dig mine out and give it another chance.
I like the idea of putting this on a tripod. The small package makes for easy storage and transport, but you have to have a table or a car hood to use it. I'll try the Barlow trick this week!
Actually it does: these how are cheap non-true bird jones are built. Like powerseeker 127/1000.
Biggest problem is that you can't focus on both central and peripheral field of view, barlo effectively cuts outside FOV
Hello, Mr. Dreese;
Thank you for another excellent video!
Today I learned that using a mask can change the F ratio of a telescope. (Thank you!)
So would this work on my Orion StarBlast 6?
Now to figure out how changing from a f/4.9 to a f/6 or f/7 would affect the viewing.
BTW, I bought a Celestron CG-4 (on sale) & mounted my OTA.
Huge improvement in how steady & stable it is.
It especially helped my light-weight 70mm refractor.
It is amazing how much the stability has improved the views.
I love your videos! Thank you so MUCH!
Mostly I watch hand tool woodworking & Suspicious0bservers w/ a bit everything else.
Your videos are usually informative, educational, AND entertaining.
In your opinion, which would you buy, an 8" dob or a10"; I'm leaning toward an 8".
Clear skies!PS
I already subbed, now you have my bell, sir!
The Orion StarBlast is a great telescope. The offset masks (sometimes called offset aperture masks) work great for telescopes with parabolic mirrors like yours. One of the big benefits to using them on reflectors is that it eliminates the obstruction of the secondary mirror and the spider supports - in other words, it gets rid of the diffraction spikes we see on stars. I like what you say about stability - it is so important with regards to how satisfying a view is. Dobsonians are champions at damping out vibrations. In my opinion, the 8 inch Dobsonian is as close to perfection as you can get regarding price, portability, value, etc. I used to have a chart somewhere that showed it as an optimum diameter with regard to resolution too when measured against other parameters. Like, it's the best resolution before cost and weight explode.
I suggest use with much better eyepiece.
You are getting strong CA with faster scope maybe the cheap eyepiece isn't capable of handling fast scopes. So
Also if you are doing side hole - at least make many of them - since anyway you bringing same spherical aberrations no matter how many holes you have.
I use the offset masks on my bigger (parabolic) Dobs, but as you mention, it just amplifies the badness of spherical mirrors. For this comparison, I wanted to use the cheap junky eyepieces that they ship with it, lol. But I've since found that even a basic Plossl improves the view quite a bit.
Interesting.
Glad you think so! Thank you for watching.
informative, but I would like to ask about my 700mm f/9.2 Newton, but the aperture is 114mm, however my telescope cap comes with small hole which is work like mask, around 3 inch. will that work to reduce spherical abberation?
The good news is that your telescope is already at a focal ratio of 9.2, so even if your mirror is spherical, the effects should be at a minimum. In my video, I had to use masks to get it from the default (f/4) to a good view at f/7.
Hi, great explanation on how masks work! I actually learned quite a bit from it! much appreciate it!
I have a quick question, I remember seeing a old restored apo refractor that you used in one of your videos, and I was wondering what made you choose newtonians over apo? (not that newtonians are inferior or anything optically, just seeing more newtonian related videos)
Back in the 1990's I built a six inch Dobsonian from Richard Berry's book of plans. That was my main one for about 20 years. I took for granted that Newtonians don't have any chromatic aberration... which makes sense because that's exactly why Isaac Newton invented them. So when I started buying/fixing up used refractors, the blue rings around the Moon were very irritating. Aside from the few Japanese-made long refractors, most refractors in my price range have some type of obvious chromatic aberration. Using Newtonians just eliminates that irritation. So guess it comes down to this: After about $200, Newtonians simply do not have chromatic aberration. With Refractors, that luxury doesn't start until around $600? (I think, I don't buy refractors very often).
@@reflactor ahh I see!!! yeah, that makes sense!
I wonder how Saturn looks on this scope, can you see the rings? I imagine you could also see Jupiter's moons
You can just barely see the rings with the stock eyepiece and the mask. With Jupiter and the mask, you can clearly see a large disk, the moons, and just a hint of the cloud bands. If you switch to a nicer eyepiece, you can see a bit more the cloud bands (but not much).
Excellent innovation!John. Instead of using one hole as an F stop have you tried using several smaller holes all over the stop would this make a difference?
Now that's interesting... I haven't tried that. It would work well for a parabolic mirror, but any offsetting you do with a spherical mirror just compounds the problems of the spherical mirror (I suspect).
If I remember it right, 2 holes can be used to find perfect focus, like the Bahtinov mask ;)
Since I don't have a 3D printer, do you sell these masks? I'd gladly purchased the f5, f6, f7, and the eyepiece holder.
Unfortunately I don't sell them because of the time required (they can't be left unattended). Each of these masks takes about an hour, so they would be perfect for a local library printer.
Hi reflactor! Great video but I can't really recommend this scope for little kids.they will screw up the collimation. A nice comfy 70mm goscope refractor is better I think. Clear skys forever!
You bring up a very good point. When I first opened this, the collimation wasn't too bad to be honest. I only did my "extreme collimation" because I knew I'd be testing masks. I've found that tiny cheap refractors have somewhat frustrating optics and vibrations that won't go away. Despite this things cost, it had no vibrations. Now... if you get one new that is badly collimated, that would not be fun at all for the new user.
Hi! I so what's worse? Chromatic or spherical aberration for a little kid?
@@ericfrizzell2450 I think spherical because they may confuse on how to focus. I actually own lightweight 60/400 scope and it had very minimal CA. I mean even Venus looks well with it. Optically these cheap travel-scopes achromats are usually very good - but the mount and accessories are usually garbage.
It seems to me impossible to find this channel by its name. Whenever I search Reflactor, RUclips thinks I'm searching for Reflector, and shows anything but this :(
I get the same think. That's why subscribing works best. Might take a while for it to show up in the algorithm.correctly
@@hednik I subscribed a year ago or so, have all notifications turned on, but you know - if you didn't watch the video fast enough, it goes down in the list of notifications, and becomes harder to find. Reflactor is a great name, BTW.
I had a long conversation with RUclips support (they are awesome by the way). They said that the algorithm assumes it is a typo of the word "reflector". At the top of the search results, it says so, but gives you the chance to search specifically on Reflactor. Unfortunately, that writing is very small. We came up with me just asking viewers to search on Reflactor, push the refinement link and then click on one of my videos. Seems like a tall order though. The channel may remaini hidden forever!
Love your videos. You have a gift for teaching. Wondering…. I made a mask for my Celestron Firstscope. Interestingly, the lid for my quaker oats grits box fit perfectly. However, i would like to download and have printed one of the plastic masks. Having trouble finding someone who can do that for me. Can you suggest a 3d vendor I can contact? Thanks, Mark
I haven't found any 3D vendors that charge rational fees. When I tried to find a 3D printing vendor for my smartphone holder file, the cheapest I could find was 80 dlrs per part. So I never found one.
@@reflactor So you do your own 3d printing? If yes, i will pay you to print out the f7 mask for me. Mark
Hello! I tried making a mask for my spherical mirror and it didn't do anything. My 5 inch mirror is a spherical bird jones telescope mirror. I tried making a f9 mask but nothing changed what should I do?. My telescope is the celestron powerseeker 127 eq. I have thrown away lots of telescopes and I don't want to throw away this one. Any recommendations or ideas I can use? Thank you!
Please don't throw it out. I'm slowly becoming an expert regarding the Celestron 127EQ (I own two of them). I'm making a video about the history of Bird Jones and Part 2 of that will be how to "hotrod" your Celestron 127EQ. The major realization is that collimating the 127EQ makes all the difference, but it is VERY hard to collimate properly. That will be in the video. It may be what I focus on in January.
I tried collimating both a cheesier and laser collimator but nothing seems to work. I will be on the look out for the video! Thanks :)@@reflactor
I don’t see the link to download the plastic masks?
The link is in the description box for the video. Scroll down to where it says "3D Parts Files"
Edu Science 50mm Refractor Telescope (50/600) from a well-known toy store has sharper optics, and sutable not only for the Moon, but you can see rings of Saturn, and bands of Jupiter. I was surprised, TBH.
That is good to know, especially with a small 50mm. Thanks!
Bought it at a thrift store for AU$5 to take a red dot finder off it. Now I'm thinking to put it onto my AVX mount to goof around with it and a planetary camera.
Is toys r us still alive in USA?