Thor’s Helmet

[RyanJones]

Hi all,

Presented with a great night on Saturday night, the thoughts turned to what to image next. I’ve always loved this object and I’ve seen a lot of great ones on here but at Mag 11+ I was maybe looking for something easier. Alas, with a bit of inspiration from Alexander Massey, I decided to give it a go.

Quick side note, for those who haven’t visited Alex’s website, it is well worth a look. He hand sketches objects and his work is awesome !

For this object I had to swap over all of my gear from my F/4 newtonian to my C9.25 SCT....... and this is where my problems lie..... I’m so used to using the t-ring for my camera that has my coma corrector attached to it. I totally forgot to swap to my normal one. This is where my really poor stars come from. Quite disappointing really because I’m quite happy with the rest of the image.

So here’s the capture details:

68 x 180 Sec subs
Canon 350d modified @ iso 800
STC Duo filter
HEQ5 pro guided @ approx 0.9 arc sec error
Celestron C9.25 with 0.63 reducer

Thank you for looking

[casstony]

It is annoying to get through an imaging session and later realise you forgot to set up the gear properly. The colours are great.

[Mickoid (Michael)]

Despite your mishap Ryan, you still managed a result and though you are disappointed, we can all take on board what's happened to you and relate to it from our own experiences. Saturday night had almost everything going for it and I too forgot to refocus when I moved to photograph another object. I was cross with myself for not thinking to do such a fundamental job but I still got a result albeit not as good as it should have been.

This object is quite dim and to tackle it with the 9.25 inch is quite a challenge. Was this at f 10 or did you use a reducer?

[etill (Elliot)]

It's a great shot - Saturday night was pretty good for the first time in a while.

[RyanJones]

Thank you Elliot, Michael and Tony. I’m sure my mistake is easily relatable to all of us. I guess it puts in perspective how difficult this hobby is to get good at. There are so many things to remember and that have to be just right including the whether that things are always going to pop up. With so many external issues that we face, it only makes it more frustrating when you make a silly mistake yourself.

Thank you for all for your positive feedback despite the obvious issues.

Michael:

It was on the C9.25 with a 0.63 focal reducer. The image posted here is significantly cropped as I felt there was no point in processing elongated doughnuts. It is probably about the same FOV as the full 2350mm focal length.

[LostInSp_ce]

As others have said it's still a great image Ryan. If it makes you feel better, I was shooting the Chicken on Saturday night but fell asleep. Woke up 3 hours later head on my keyboard only to find that I had cancelled the meridian flip. Hoping get about 3-4 hours of data I ended up only getting 30 mins. However, that wasn't the worst of it. When I checked my subs I found that I forgotten to plug in my dew strap so the 30 mins I did get was all ruined by fog. Being one of the clearest nights in months and a Saturday night wasted you could imagine how devastated I was!

[RyanJones]

Hi LIS,

Thank you 😊
That must have been incredibly frustrating for you. I’m sure if imaging was easy without all the pitfalls it wouldn’t have the same appeal. I guess in a way it makes us all more appreciative of excellent images when they do come along. Fingers crossed for us all that some more clear nights are on their way.

[Ant0nio (Tony)]

A credible image despite the issues Ryan. You could always try the lens distortion filter in Ps to tidy the stars up a bit or use Star Net or similar to remove stars so you can stretch the main image on its own. Just my 2c
Cheers,
Tony

[mental4astro (Alexander)]

Great pic, Ryan. Your pic has a lovely glow to it that makes it quite appealing

As for the lens mix up, it's also a good thing because it demonstrates that correctors/field flatteners are scope specific in their design. Some people may say "dah, of course", but their will be some folks who haven't thought things through enough to understand this. And the same goes for eyepieces - some EPs will perform just about flawlessly in fracs and SCTs and Maks, but in Newts they exhibit a range of aberrations - and it is not because the EP "is crap"... And the tremendous variation in f/ratio and associated optical properties challenge all EP's.

To have an EP perform well in all scopes types is exceedingly difficult & are typically expensive, but not always. Because of the complex nature of contemporary EP design, you may find an individual focal length or two from a given line that doesn't perform especially well in Newts (because the line was not designed for them) that one or two individual pieces are actually also outstanding in Newts.

I know the above talks about aspects of visual and not imaging, but the optical principles between the two don't change. But it may also have some people rethink some notions about aberrations they may see in their EPs and even their imaging optical train to achieve better results

I used to try to find EPs that "performed" perfectly in all my scope types from fast Newts through to fast and slow refacs and my Mak & SCT. This only created eyestrain for me (an aberration that is NEVER spoken about) but I also noticed performance differences over time that were just distracting and annoying. Today my EPs don't cross pollinate - I have a set that I keep for my Newts and a set for fracs & my Mak, though two or three I can use in all, but that's 2 or three out of 16 EPs. And they are not of the Brands you may think.

Alex.

[RyanJones]

Thank you Tony and Alexander,

Tony - I have used some lens correction in this image. I find it works quite well too but there’s only so much lipstick you can put on a pig 😝

Alexander - I totally agree that it’s important to understand what each part of your optics is doing even just in a general sense. Knowing what is happening to the light as it enters and exits your OTA gives you the ability to be much more aware of what is causing faults or flaws and how to correct them. Also it gives you a fair idea of what will and won’t work in a certain image train before you hand over your hard earned for it.

[ChrisV (Chris)]

Very nice Ryan. Ha, I've done same with my coma corrector. Put it on a refractor after using the newt (and visa versa) ... I think the reason is that looks a bit like the T-2" adaptor I use for that scope. Well that's my excuse anyway, or just general stupidity.

Go on, redo it without the corrector. I reckon it'll be a winner with your SCT !

[RyanJones]

Thank you Chris. That’s exactly the excuse I was running with but it is just an excuse lol. I will give it another crack..... properly this time. I’ve just got to wait for the clouds now....