today's video is sponsored by squarespace this is the new Askar fra 300 pro the fra
in the title of this telescope stands for flat field refractive astrograph and for
anyone that hasn't heard that term astrograph it means a telescope specifically designed for
astrophotography rather than for visual use like with an eyepiece
now we can usually adapt a visual telescope into one more fitting for astrophotography by adding on
a field corrector like a field flattener if it's a refractor or a coma corrector if it's a reflector
but if you're designing a telescope from scratch specifically for astrophotography then it totally
makes more sense to design these flat fielding correcting last elements right into the design
of the telescope which is why this is a quintuplet meaning there's five pieces of glass inside the
tube here which of course makes this telescope fairly heavy for its size but the idea is that
we won't need to buy anything additional with this telescope to get a flat well-corrected
field for astrophotography and for that reason and also because they're more of a specialty product
astrographs are typically very expensive but this one the askar fra 300 pro is very competitively
priced at just 949 us dollars so i thought it'd be interesting to see how it performs and
in this review i'll be putting this telescope through its paces and seeing how it stacks up
with another popular small telescope i have here this is the william optics redcat 51.
hi everyone this is nico carver and this is a review so first some disclaimers
both uh the askar fra 300 and this redcat 51 were sent to me free of charge for the purpose of video
reviews the redcat 51 from wo boys which is the u.s online store for williams optics telescopes
and the askar from askar directly but with assistance from agena astro products none of
these companies have any input into what i say into this or any future video on these products
and no money has changed hands these companies may choose to share my youtube video or my photos
taken with the products on their website or social media but that's completely up to them throughout
this video i'll be comparing the askar fra 300 to the william optics redcat51 because i see them as
competitors in that they have fairly similar specs the redcat is also an astrograph meaning the field
flattening elements are built in it's a quadruplet it has a front aperture of 51 millimeters a focal
length of 250 millimeters so that gives it a focal ratio of f 4.9 the askar on the other hand has a
front aperture of 60 millimeters a focal length of 300 millimeters so that gives it a focal ratio of
f5 so f 4.9 versus f5 but this one's a little bit longer so they're very similar in a lot of ways
you're going to get a slightly different field of view askar did say they added pro to the end of
this title because this is an f5 scope while their other fra telescopes the 400 the 500 and the 600
are f5.6 astrographs and that small improvement is important for uh photographs because that extra
half stop of light means that the photos will be brighter faster and that's why focal ratio
is sometimes referred to as photographic speed especially if you come from the world of lenses
and it means that with a faster telescope one with a smaller f number which remember is a
ratio you can take shorter exposures but it also means your signal-to-noise ratio will be better
compared to a slower scope if we're talking the same total integration okay on to the comparisons
in terms of weight with a vixen plate a ring and a top handle installed the red cat weighs
1.8 kilograms or just over 4 pounds while the fra 300 weighs 3.4 kilograms or 6 pounds 11 ounces the
red cap package includes a soft carry case but no top handle for a guide scope if you do want
a top handle it costs 50 extra dollars the fra 300 does not include a carry case but is well
equipped otherwise because it has both a top handle and a synta style finder shoe attachment
and so for astrophotography i think most people would put the guide scope on up top here something
like this and then with this finder shoe maybe put like an asi air or something like that or a
power bank something that would be useful right there for all the cable connections in terms of
focusers the askar has this more traditional uh 2.5 inch rack and pinion design focuser with a
single speed knob on this side and a double speed knob on the other side this red knob here is a 10
to 1 reduction which is very nice if you manually focus like i have been with these telescopes
if you do want to add an autofocuser the bottom has mounting holes already for adding something
like a zwo electronic autofocus or eaf if you want to add auto focusing to the red cat with the zwo
af you'll need to buy a pulley system i have this excellent one sent to me by deep sky dad
and the reason you need a pulley system is because the red cat has a helical focuser like this like
your camera lens i have heard that in version two of the red cat that it's slightly different that
this front element doesn't go in and out when you move the focus ring but that it is still a helical
focuser both telescopes have a locking device for locking the focus this one right here this one
underneath as well as a knob for manual rotation which is very handy on the red cat it's right here
and on the fra it's right there and i love having a little locking mechanism for a
manual rotator it's much better than having to like rotate the whole telescope in its ring
um it's much handier and works much better and i'm really big into picking my rotation angle so
that's a really good feature of both telescopes in terms of mounts for these telescopes if you're
pairing them with a lightweight dslr or mirrorless camera or one shot color astronomy camera i think
you could go with basically any uh mount including this new sky watcher star adventure gti uh if
you're using a mono camera with filter wheel like i have here the red cat would be the safer bet
because you'd be well under the weight limit of the gti but it actually amused me that the fra
300 with this qhy 533m and a full filter wheel this kit that i have exactly right here put me
right at the payload limit of five kilograms for the gti so i actually haven't had a chance to try
out this exact combo yet but i intend to because i actually think this would be a really awesome
lightweight sort of travel setup before i show some various photo results and star tests done
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so next up is what i'm sure many of you really want to see which is how do these scopes compare
when it comes to a star field and a full-frame camera so i shot a three minute guided
exposure with match settings on the canon eos ra on both telescopes on the same object which
is the blue horse head nebula here and i shot uh this within like a 10 minute window so there
wasn't much time between these two exposures so i think it's a pretty fair comparison on the stars
and this is the full field with the redcat this on the right is the full field with the fra
300 and the first thing you'll probably notice is that it's a different crop or you know or it's a
different field of view i should say uh the fra 300 is a little bit tighter in than the red cat
but that's understandable since the red cat has a focal length of 250 and the fra 300 it's 300
millimeters the other thing that really stands out from just a single exposure that's not calibrated
is that the red cat has pretty significant fall off vignetting in the corners while it's pretty
well illuminated in the fra300 so you can see that's pretty noticeable fall off here
while on the fra 300 you can see it gets a little darker in the corners but not
not as bad but that fall off in the corner is not really going to impact your astrophotography
that much unless you don't shoot flats but i always shoot flats and so after full calibration
of these two frames they look quite different like this and so you can see here now they're looking
a little bit more similar both very flat and i don't you know i've looked at the corners
and i know that the theory is that you're going to have much worse signal-to-noise ratio when
you have that much light fall off but i don't know i've looked in the corners of these
shots and i don't really see a huge difference in the noise at least visually so that gives
you a sense of that next up let's look at some stars really zoomed in so for this i'm going to
go into image analysis
aberration inspector
and run this on both shots here okay and there we go and at first glance to my eye
i mean these both look quite good i don't really see you know glaring uh problems with the stars
but let's go ahead and zoom in on the center here okay um you know they're both what we call
under sampled so it was zoomed in this far this is probably like 400 zoom you can see a little
bit of uh blockiness to the stars like they're not you could you start to get a little bit of
pixelation or whatever um but they they both look fine i don't see a huge difference in sharpness um
let's look at the corners now okay so
this left upper left corner i can think i can see just a little bit more chromatic aberration
a little bit of like red separation on that star um but unfortunately these aren't like perfectly
matched fields so i don't uh have that same star here to compare like a big star right on the edge
uh so i don't know if that's the best comparison but i think i see a little bit of red fringe
there while on the red cat stars i don't really see much of anything now i mean this level of
chromatic aberration wouldn't bother me i don't think but it might bother some
people so i just that's why i'm noting it yeah and i think you know here let's see if there's a
okay so here's a fairly good test like that's a bright star fairly close to the edge there's a
bright star fairly close to the edge and i i still feel like i see just a little bit more
of that like blue and red um separation here with the ascar than i do with the red cat
but let's keep looking so in this corner this is the bottom right corner the star shapes look a
little bit um off on the red cat and a little bit more circular a little bit more round on the ascar
there could be a tilt issue there so it might not be the optics fault let's go to the upper right
corner yeah same thing in the upper right corner a little bit not as extreme as that
that bottom right corner but in the upper right corner i see a little bit more um
malformed stars on the red cat that i do on the ascar i think but you know what this
is all sort of nitpicking because i think all of these stars look very good um i'm you know
i'm suitably impressed that these are 250 and 300 millimeter focal length on full-frame camera that
i think these are both quite impressive uh for you know scopes that are under a thousand dollars
i don't i don't know what other people think but uh for me this this is a very impressive
performance uh to wrap up here i i haven't had the best luck with weather with this scope yet
um but i did get this finished image done here at home in somerville this is with the qhy 533
m mono camera and a hydrogen alpha filter and an oxygen three filter and it's just
eight uh exposures with the h a filter and five exposures with the o3 filter so not a lot of data
um but it just i think it shows you the potential of pairing the fra 300 with the 533m uh it's an
interesting combination i think i think a good combination of gear i i just think this this
field of view 300 millimeters with that one-inch square sensor is going to work well for a lot
of these sort of nebula scenes like the jellyfish here with the extended uh nebulosity and the two
bright stars in in gemini and uh you can see that i don't see any issues with you know star haloing
or anything like that with that's with this setup so uh hopefully this review of the askar fra 300
was helpful and if you have any questions you can always leave them in the comments
and i'll try to answer them all until next time this has been nico carver clear skies