Chris

Just an off the cuff video covering some astrophotography options between £0 and £400. 

It looks like the new Star Adventurer GTI will be in the next bracket up so I didn't mention that one.

The black hole sounds haunted! 😮

Nice! Thanks for sharing. 

Hey Dan, I take it you've ruled out the ISS on the second pic? 

22 minutes ago, Paul_Sussex said:

Chris - just hoping I can see something that clear with the 6" F/8. (Or was that AP?) And loving the Youtube channel as well!

Hey Paul thanks! Well you'll definitely see the planets nice and clear with a 6" f/8, the f/8's are a real planet killer. The above was just a handful of 3 minute exposures stacked together, I'm not a hard core imager but Just like to tinker 🙂 

22 minutes ago, Mr Spock said:

Depends on the size - my 12" springs were weak and the scope wouldn't collimate without clunking and the mirror moving. Stronger springs fixed that. What doesn't help is the collimation bolts rubbing on the cell holes. Some sort of plastic sleeve would help here and perhaps even remove the need for stronger springs. Still, you have to remember how much the scopes cost when sizing up fancy details like that 

Fair point Michael, your 12" mirror is going to weigh a whole lot more than my tiddly 6".  

I was worried about the springs when I decided to test the GSO / StellaLyra 6" F/4 imaging Newtonian, however I've been pleasantly surprised! In fact I've been imaging with the scope and I still haven't got round to collimating it despite it travelling from China to Exeter, then Exeter to Ipswich. Collimation isn't perfect yet and it does need a tweak, but this is the first time I've ever managed to get any kind of image out of an f/4! despite owning two f/4's prior to this one! 

I've not cracked the spacing for the coma corrector yet but I'm just pleased that the whirlpool galaxy looks like the whirlpool galaxy lol Looking through one of my previous f/4's was like being on an acid trip! 🤪

1 hour ago, Louis D said:

I hope this isn't a stupid question, but why does the no filter image have the most color shift of the four images (I see it as pink on my monitor)?  Did you use a weird color balance on your camera for all four images, and it balances out the color shift of the filters on the other three but ruins it for the no-filter one?  It just seems counter intuitive that the filtered images are more neutral than the unfiltered image.

Sounds like an excellent question to me  Exactly what Vlaiv said, I'm using the ZWO ASI462mc which has a very strong red and IR response. The filters are doing a good job of cutting this out

2 hours ago, Ratlet said:

The image seemed sharper with the semi apo than with no filter.  Do you think that is an effect of the filter or improved seeing?

Hi, I suspect it's more the filter because the semi apo filter cuts UV/IR wavelengths as well as cutting chromatic aberration. 

In hindsight it was a bit pointless stacking the Semi Apo with the UV/IR cut filter because I was forgetting that the Semi Apo already does the job of the UV/IR cut filter!

1 hour ago, bosun21 said:

https://www.firstlightoptics.com/reviews/baader-contrast-filters_US-ATT_review_0414.pdf
Here is a comparison between the Semi Apo, Fringe Killer and the Contrast Booster 

 

 A good read that, thanks for sharing  I prefer filters with minimal colour cast so side with the author with regards to favouring the Semi Apo. I confess I didn't keep the contrast booster long when I had one but wouldn't rule out giving it a second go purely for the imaging side of things as you can play with the colour balance in post. The fringe killer is one I'm yet to test!  

10 minutes ago, vlaiv said:

It is always worth adding simple wratten #8 filter to these comparisons as it is by far the cheapest option for dealing with blue fringing in achromat scopes.

I'll add one to my next order Vlaiv, it will be good to compare. 

This is more of a practical review/test rather than a write up. The Baader Semi Apo cuts the IR region of the spectrum just like the Baader UV/IR Cut filter, therefore this is mainly showing the importance of using some kind of IR cut when imaging with at least an achromat refractor (*Unless you're specifically targeting IR wavelengths with an IR pass filter).

37 minutes ago, vlaiv said:

Why do you think you'll tweak that advice?

You think that above image is well sampled at 0.39"/px - although it is presented at 0.5"/px and has FWHM of 1.9"?

One of two images below has been reduced to 50% in size and then resized back to match the original. Which means it was sampled at 1"/px at that point. If detail is there in the image that needs higher sampling rate than 1"/px - then that detail should suffer. Can you tell which one of two images was resized to 1"/px and then up scaled back to original size? (Actually you should be able to tell as it has less noise, but all the detail is still there).

My answer is they both look great 😀

Fabulous detail! I tend to suggest people aim for around 1-2"/pixel when matching cameras to a scopes, however I may have to tweak this advice after seeing your SCT in action at 0.39"/pixel!

Plenty depends on the mount though as there's no point smearing photons. 

Just a quick test shot of M63 Sunflower galaxy so far, the extension rings I've ordered for the coma corrector are stuck in the post so no coma corrector used and just cropped instead. 30 x 100 second light frames using a Fuji XT1. 

1 minute ago, rsarwar said:

excellent review chris!

do we know what the image circle is of the CC with this scope - maybe a flat image with an APSC or full frame camera. the product page on FLO only states 44 mm clear apparture. 

also curious if it will work with a 130 pds.

Thanks glad you liked it Well the coma corrector shouldn't vignette much at all with a full frame sensor as it has 44mm clear aperture, however as to how well it corrects star shapes to the edge with a full frame camera I do not know. Most of the reviews out there are for fast Dob owners using it as a cheap alternative to a paracorr.

I will be testing the coma corrector with an APS-C  Fuji sensor and adding to the information regarding the imaging side of things. The few imaging reviews I've seen do indicate it would be decent at f/5 with your 130pds, although they don't mention the sensor size! 

One thing to note is that the GSO/StellaLyra photo-visual coma corrector requires a slightly unusual back focus of 75mm as apposed to the typical 55mm so a 20mm extension tube will be required as well as your T-ring. 

I've kindly borrowed the 6" model to play with as well as the StellaLyra Photo-visual coma corrector (Yes I'm like a kid in a sweet shop!) Anyway, to begin with here's a video overview plus out the box collimation check. Once I've MacGyvered an extra counterweight to balance the scope on the mount I'll attempt to do the scope some justice and pop out some pics

Thought I'd do something beginner friendly so here's a video on the fundamentals of balancing an EQ mount, plus some tips and tricks. 

The StellaMira I was kindly loaned is going back this week so I've put together a quick review video before it goes: 

Bodes, Cigar & NGC3077 - 18 x 5 minute light frames with the SM 90 EDT + 0.8 RF and Optolong L-eNhance, Fuji XT1 ISO 1600. Processed in GIMP. 

I know the 3 back to back storms weren't actually my fault, however they did happen to coincide with the purchase of my Sky-Watcher Evostar 120 achromatic refractor. I think I broke my record for delayed first light but Wednesday night was lovely and clear, and my neighbour didn't have his array of light canons switched on so I grabbed my chance for first light. 

After having a quick peak at Procyon to check out the intra and extra focus Fresnel rings which initially look promising, I turned the scope south towards the sword of Orion. You guessed it, the Evostar's first DSO was to be The Great Orion Nebula.

I tapered my expectations based on the street light point blank at the bottom of my garden but I was still treated to some nice nebula on show. The trapezium stars A to D were visible at the low power of 40x magnification with my trusty 25mm Plossl, and I was reminded of the pin prick stars and velvety sky when observing with a refractor which is always a good thing to be reminded of. 

Me being me I recorded First Light with one of my usual videos, and after the camera was packed away I settled in for some me and the universe time which a swear should be classed as a form of therapy.

9 hours ago, Chriske said:

Hi,

Has someone ever taken images of the sun with a Lunt35 scope..?

Chris

Yes I did a few years back. I made a little video at the time:

The Mica made the Gauge Block look like the Himalayas! 

Very very nice Michael! Congratulations and looking forward to hearing all about first light

On 13/02/2022 at 14:28, mikeDnight said:

I talked a friend into buying a 100mm Helios way back in 1999 as I didn't have the courage to pay for a scope made in China. First light through that little achro, which I think cost my friend £245, settled my suspicions, as the stars were sharp and any CA was very well controlled.  There was no moon in the sky so we spent the evening checking out a few Messier objects and simply sweeping through star fields. I remember M1 revealing a N shaped tructure within its nebulous glow. The following day I ordered a 100mm for myself, but the day after I changed my mind and altered the order to a 120mm F8.3. The price for the 120mm Helios, which came with a beautiful EQ3, 90° mirror diagonal, 2X Barlow, and three lovely silver top plossl's, was a miniscule £275. First light was on a crescent Moon, and my first thought was "Where's the CA?"  There was CA of course, but it was nowhere near as bad as I'd expected. The 120mm Helios achromat was a joy to use.

Within a year or so I'd bought a 150mm F8 which was superb as a deep sky/comet seeker. Galaxies and nebulae drifted effortlessly into its field of view. Again, there was observable CA around the Moon and the brightest stars, but this was never made to be a lunar and planetary scope.  It's speciality lay in its ability to deliver wide, rich star fields, and the study of nebulae and star clusters. The 150mm was a perfect comet seeker!

The down side to these Chinese achromats became evident over time, as other observers bought their own Chinese achromats. The problem was never the CA. Such scopes will always show CA, its the nature of the beast. The real issue was spherical abberation, which was highly variable from one scope to another. Some were so bad they were unusable and had to be returned. However, when you got a good one it was an awesom beast!

On a side note, I never found any kind of filter to improve the view in terms of counteracting the chromatic abberation. I prefered the natural look. Of course a UHC or OIII can be very helpful on some fuzzies.

Good to read your experience with these achro's Mike, and it echo's my experience so far.

I bought my first EVo120 in 2005 (old blue tube on a black EQ5 mount) and loved it, really sharp for an achro and the CA wasn't bad enough to be washing over bright objects like some of the larger F/5 Startravels. I reluctantly sold it when moving into a 1 bed flat but later picked up a second hand Evostar102 f/10 when we moved into our first house in 2010. This one wasn't quite so good with SA like you mention, it just lacked sharpness at higher powers. 

I agree that the CA is a known commodity, and there is even the infamous chromatic aberration chart that often appears! However the SA can be slightly pot-luck which may be expected for any mass produced affordable scope. 

I'm hoping for ok levels of SA, the FLO sticker on the box is sadly spitting the truth regarding the clouds so far so still no first light yet!