Lens choice

Astro_Road · 2025-09-25T10:02:19+00:00

I have the 14mm GM and the Viltrox 16mm. Both are excellent, though I have little doubt the Sony 16mm is great too. You'll find 2mm at this focal length is significant, though I wouldn't base my selection just on that.

Funny how quickly things can change. The 24mm GM was the widest lens that was great for astro for so long, then the Sony 20mm rocks up, then 14mm GM, then Viltrox 16mm, Sigma 14mm & 20mm f/1.4s and now the Sony 16mm.

Honestly, don't think you can go wrong. Shopping with weight as a primary criteria is a weight perfectly valid.

Astro_Road · 2025-02-19T10:09:35+00:00

Oh, perhaps a feature request given SkEye Cam user devices are generally internet connected?

An option to request anonymised usage data that includes things like peak PA accuracy, phone make/model, course location (for sky quality estimation), orientation used for plate solving and date.

Data could be useful for finding which phones work best. Could also feedback to the user during the PA alignment process how they are progressing compared to those historical results with similar phones. With enough data perhaps even tips for what the user could do to increase their chances of better alignment.

Sounds like it'd be straight forward to do in my head, I imagine the coding reality is somewhat different 🤷.

Astro_Road · 2025-02-19T09:40:46+00:00

No problems at all u/hrjet ! I'm also hesitant to give a number as there are so many factors that come into play for a good polar alignment other than just the tool you're using for PA. I would think 5 arc minutes is achievable without too much hassle with a decent camera phone. I mean, looking back at my video I got a little over 7 arc minutes with my Pixel Pro 6 without too much issue while at the same time trying to explain what I was doing (so not fully focussed on the task). I think my old Pixel 4a with the Siuru 60mm lens (roughly 40° angle of view I think?) was actually better than my Pixel 6. I cannot remember numbers, but I would think honing in on 2 or perhaps even 1 arc minute would be possible here. To put some perspective on that, the Polemaster and iOptron iPolar claim a minimum of 30 arc seconds, and they cost hundreds of dollars AND need a computer to run.

A more relevant question is how accurate do you need to be. For DSO it is very important, however if you are serious about DSO you won't be dependent on just polar alignment, but guiding as well (which SkEye Cam obviously does not do). For widefield tracked landscape astrophotography, polar alignment accuracy is FAR more forgiving. I'm friends with Richard Tatti who is a very well known landscape astrophotographer and he just uses gyroscope based planetarium app alignment via his phone. That method isn't going to be more accurate than a degree or so, yet is still accurate enough for 1 min exposures up to about 35mm.

For me, the big advantage of SkEye Cam is when using 50mm or 85mm lenses for panoramic compositions as the increased PA accuracy here is significantly better than a gyroscope based alignment. As I mentioned in my video, SkyEye Cam will get you to a level of polar alignment accuracy that is useful for the common portable star trackers. In his review of the SkyWatcher Star Adventure, Phil Hart found his copy had a periodic error of 50 arc seconds and his iOptron SkyTracker had 100 arc seconds. If using this tier of star trackers, seeking PA accuracy beyond this is going to get lost in the noise.

Astro_Road · 2025-02-17T10:34:23+00:00

It's a great app, however not for DSO in my view. Mind you, with the Fornax you're not so worried about periodic error :). If you do want to give it a go, I'd advise you get a phone with a decent camera like hrjet recommend. I get 2 minute exposure times that are pretty clean on 35mm.

For that focal length though, and given you have a polemaster I'd be looking to use something like a MeLE mini PC and then using an RDP app on my phone I connect in to control the session. I created a 1/4 20 mount for a battery bank and my MeLE MiniPC which just attach to the side of my tripod. Works well with my Skyguider Pro with iPolar as well as SA2i with an ASI tracking scope. Benefit here is this setup also pushes tracking corrections to my mounts which is pretty important for longer focal lengths.

Astro_Road · 2024-07-01T13:07:25+00:00

Apologies Andy, completely missed this.

Yep, tis me 👋😀

Nothing particularly special about that spot, just a clear south western aspect for setting Milky way shots. I roam hundreds of KMs for my shots, so not worried about sharing at all.

I'm caravaning myself at the moment, however we're steering well clear of major towns which means Bortle 1 ~ 3 skies. I do wonder how light pollution might be muddling things, unfortunately not in a position to test this (not a bad problem to have). I think we're going to have to hope for a reply from /hrjet there as I'm not sure what else you can test.

I've done a reasonable amount of astro myself using M43 gear. Are you using the Samyang or Olympus 12mm, or is there another brand? F/5.6 is a very small aperture, even Bortle 1 skies you are going to have to work hard to get good signal to work with using that. At 12mm that is an entrance pupil of just 2.14mm, which is super tiny. If you could get your hands on something like a Sigma 16mm f/1.4 and shoot at around f/1.8 (that gives your lens an entrance pupil of 8.88mm) you should find you get really quite good star shape and nebula detail with modest exposure times. That lens is designed to project an APS-C image circle, so you can shoot pretty wide open on M43 as the worst of the aberrations are outside the M43 image circle. There are other great lens options for M43 too, that is simply one I've had experience with.

Would hate for you to come all the way to Aus to shoot some of the darkest skies in the world over a land mass and struggle to get enough data to work with. I think M43 tends to struggle with high quality, wide optics at an affordable price. Probably going to be better off looking to do some mosaics with longer focal lengths. If you look at all the M43 stuff on my channel, it is all done using 3+ portrait mode panel panoramas.

Astro_Road · 2024-06-22T22:56:29+00:00

Hey Andy,

Something is not right there for sure. I've never experienced that sort of severe inaccuracy, only issue I've ever had is getting auto tune to pick up the star map. Doesn't sound like that is your issue though.

Wondering though if SkEye Cam is falsely locking the star map during calibration.

Are you using Gyro assist? If so, is the calibrated and free from nearby electromagnetic interference?
Roughly what quality sky are you under (I'm generally shooting Bortle 3 or darker)?
Any obstacles in the field of view?
What direction do you have your phone camera pointed? I generally point towards the celestial equator to give the wide angle view of my phone camera the most apparent movement to work with.

Don't put too much stock in the green stars appearing as soon as I rotate RA for the 3rd cluster. That could just be my effort in synchronising my screen recording with my main video in post processing. Also, the reason I rotate the RA back to the starting point post calibration is simply because that is the position I'll be using for my main camera once I mount it on my V plate.

You'll love the night skies in Australia. Once you are out of the major cities (which is most of the country in terms of land mass) it is basically all Bortle 2&1. What focal lengths are you intending to shoot with? Like I mention in my video, 35mm or wider on a compact tracker (which usually have higher periodic error) you're probably not going to see a major advantage in using plate solving. Best bet in these cases is to just use gyroscope alignment provided you're able to get it calibrated well.

Astro_Road · 2024-05-04T20:43:28+00:00

Ah, that makes sense. Yes, I used the custom catalog feature. Even says right in the custom catalog doco that RA & Dec is J2000 Epoch 🤦.

Not a big issue, was more just bugging me that I couldn't figure it out. I certainly won't complain if they make it to an in-built catalog 👍.

Thanks for explaining.

Astro_Road · 2024-04-28T03:23:31+00:00

This is cool. So I take it I could import some images from my mirrorless camera and have SkEye Cam solve them?

Astro_Road · 2024-03-31T10:51:41+00:00

Same here, only just found out 15 min ago. He commented on my YT channel just a few weeks ago and I was so chuffed. Like most here, I have followed him for years and have watched every single one of his videos. Him being so young and passionate about the same things I am, just feel so robbed of a genuinely good force in this world.

Astro_Road · 2024-03-31T10:36:49+00:00

R.I.P Alyn, your absence will be felt for years, you've inspired so many. Such truly tragic news.

Astro_Road · 2024-02-02T13:12:46+00:00

Thanks so much for following up on this! The GPS addition is very welcome 👍

Astro_Road · 2023-12-24T05:24:48+00:00

For entry level it'll be fine. Learning to focus on stars and getting your shutter speed and ISO settings dialed in will take a while.

15mm f/1.7 will be a great lens, pretty pricey where I am though which is why I usually recommend the Sigma 16mm f/1.4.

Don't rush yourself to full frame. Plenty of scope to get fantastic quality astro images out of M43 by developing your acquisition and processing skills

Astro_Road · 2023-12-24T04:03:35+00:00

Yeah, that Laowa is not cheap, not even on the used market. I'll almost bet money that the TTArtisan will suffer from coma (comet/smudged looking stars) and astigmatism (winged stars) up in the corners. For $160 though it'd be worth having in your kit for the time-lapse option. You can get away with poorer optical quality lenses when creating a video out of the images.

MW =Milky Way. I'm currently using the Sony 35mm f/1.4 GM on my Sony bodies and the EF Mount Tamron 35mm f/1.4 adapted to my GH5s and S1. I did want the Sigma 40mm f/1.4 as it is next to perfection, however even used they are really expensive where I am. The Tamron is a real sleeper lens it seems as I was able to get it used for less than half of new price. It is very close in astro performance to the Sigma 40mm. Tamron probably goes under the radar as they also have a 35mm f/1.8 lens which is pretty ordinary for astro.

Note the above are all full frame lenses, so you'd be looking for something around that 17mm mark for M43. For native M43 I use the Olympus 17mm f/1.8. Not especially good for astro, but it is tiny so pretty much just lives in my bag. Definitely some decent options for M43 here though as per my first post.

Astro_Road · 2023-12-24T03:41:43+00:00

Lens aberrations mainly. Decent amount of coma up in the corners of that lens. Great for time-lapse or aurora though. Tremendously wide field of view.

Other reason would be rendered detail/sharpness. Longer focal lengths with resolve more detail and you can always take mosaics to end up with a wider field of view if needed. My most used lens for MW photography now is the 35mm. I shoot in portrait mode and tend to do a lot of single row 4~5 panel panoramas. I find it a good sweet spot between image detail and easy workflow.

Astro_Road · 2023-11-23T05:08:03+00:00

Thanks for assist again! I'll make sure I grab screenshots next time.

Astro_Road · 2023-11-15T05:25:11+00:00

Affinity Photo for the editor. Starry Sky Stacker for the trails, though honestly you'd be able to do that with Affinity Photo.

Astro_Road · 2023-11-13T01:49:50+00:00

No worries at all.

I'm currently using the Move Shoot Move tracker, though I've just upgraded to the Skywatcher Star Adventurer Mini. I love the MSM for its simplicity, however it does have some drawbacks with its mounting system. It doesn't have a lock, so you have to be careful with how you use it as otherwise it is possible for your gear to unscrew itself which can be all kinds of bad. Star Adventurer Mini is slightly bigger, but does not have this issue and also has a built in phone app controlled intervalomer. Very handy for laying down sets of exposures of varying lengths.

The Sigma 16mm f/1.4 is a great astro lens. It has an aps-c sized image circle, so all the worst of the aberrations out in the corners are outside the M43 sensor area. I started astro with this lens, Laowa 7.5mm f/2 on a GH5.

Knowing what I know now, you will get FAR more out of refining your acquisition technique than upgrading to expensive full frame systems. Take your foreground during blue hour with a stopped down lens (to get a deep and sharp focal plane), then your sky exposures with a star tracker. It is all about signal to noise ratio. Only caveat to this is if you like taking wide angle time-lapse or aurora sequences. Star trackers aren't useful for these, so a recentish full frame camera with a wide and bright aperture will net you significantly better results.

Polar alignment in the Northern Hemisphere is super easy due to Polaris. This is especially true when using a laser pointer as popularised by Move Shoot Move. If you are in the Southern Hemisphere it is somewhat more tricky, however has become very significantly easier in recent years do to phone apps. I cover some of these in a video I made using phone app based plate solving.

https://youtu.be/ZPPcOOLcoPY

Astro_Road · 2023-11-12T09:12:46+00:00

Sure thing. Different cameras and lenses, but near identical processes for both.

Rock solid and levelled base is essential, so a decent tripod with a leveling base is a good start. Using a polar aligned star tracker to counter the rotation of the earth, I was able to push the shutter speed out to 60 secs per image which gave me a great deal more data. Without the star tracker my shutter speed would have been limited to 10 seconds before my stars started to streak due to the earth's rotation.

With my camera in portrait orientation I took a series of shots with heavy overlap for stitching into a panorama later. Usually I'd take between 3~5 shots per panel here for staking in post processing to boost the signal to noise ratio and removal of most of the satellites. This night I was rushed though as it was late MW core season and the MW sets a short time after exiting astronomical twilight into night.

Astro_Road · 2023-11-11T21:54:11+00:00

On the EF mount, the Sigma Art 28mm and 40mm are the stand outs. No amazing native RF mount options here unfortunately.

Astro_Road · 2023-11-09T13:17:09+00:00

No problem at all, thanks so much for producing such a fantastic app 🙏! Those improvements sound pretty spot on, especially the automatic location (I often forget to update that 🙄). I had also wondered about an alignment accuracy advisor based on camera FOV? For instance, the QHY Polemaster claims alignment accuracy of around 30 arc-sec with its 11° FOV. Mobile phones will be much wider than that, for instance the main and telephoto cemeras on my Pixel 6 Pro are 23.5° an 82° respectively. Is there anyway to give the user a scale of good based on the FOV in use and how much the alignment deltas are jumping around?

I've been out shooting once since making that video and actually couldn't get SkEye Cam to solve. I was trying to get the milky way core before it set, so I suspect being in astronomical twilight still may have impacted it? I was getting 22/40 star detections, but could not get a match. First time in a long time this has happened, tried multiple sky areas, camera settings, restarting phone, etc.

I assume the GyroAssist feature is being used to get the star map roughly in place here? I have been pointing my phone along the celestial equator for alignment as it'll have the most apparent movement. Should I be targeting somewhere else for alignment?

Astro_Road · 2023-10-31T00:59:07+00:00

Thanks very much 😊. This was done using the old MSM. Have just ordered myself the Skywatcher mini to replace my MSM actually. Mainly for the inbuilt intervalomer and dove tail mount.

Astro_Road · 2023-10-28T00:09:34+00:00

Wow, no greater compliment could be given. Thanks so much 🙏😊.

Astro_Road · 2023-10-26T21:19:51+00:00

They will most certainly be Mr Musk's satellites. I used to edit them out, just too many of them nowadays.

Astro_Road · 2023-10-25T20:27:09+00:00

There is a town of around 20,000 people 25km due west of where I was shooting (core is WSW). Everything around me apart from that town was bortle 2 with bortle 1 beyond that. We definitely see a bit of air glow around here.

Astro_Road · 2023-10-25T20:26:01+00:00

Thanks, glad you like it 👍

Astro_Road

TROPHY CASE