Lorsque vous devez choisir entre un télescope Dobson de 8 pouces ou de 10 pouces, il est utile de prendre en compte vos objectifs d'observation principaux. Pour l'observation des planètes et des objets du ciel profond plus lumineux, les deux tailles offrent des performances excellentes. Si vous êtes intéressé par la photographie astronomique basique à l'aide de votre Canon Rebel T6, tenez compte du fait que les Dobsoniens ne sont pas idéaux pour l'imagerie à longue exposition, mais peuvent fonctionner pour la photographie de la Lune et des planètes.
La différence de prix entre les modèles - environ 500 dollars pour un modèle de 8 pouces contre 700 dollars pour un modèle de 10 pouces - représente une considération importante. Bien que l'ouverture plus grande offre une meilleure capacité de collecte de lumière, vous pouvez également envisager si l'investissement dans une base GoTo améliorerait votre expérience d'observation. Cette décision dépend finalement de savoir si vous privilégiez la commodité de la navigation manuelle ou la collecte maximale de lumière dans votre budget.
C’est un excellent résumé des compromis à faire. Le point sur l’astrophotographie avec un Dobson est crucial : j’ai moi-même essayé avec mon reflex et, effectivement, seules la Lune et les planètes sont vraiment accessibles sans une monture équatoriale. Votre mention de la différence de prix, environ 200 dollars, me fait pencher pour le 8 pouces, afin de garder un budget pour des oculaires de qualité. Ceux qui ont opté pour le 10 pouces, le gain en luminosité sur les nébuleuses faibles justifie-t-il vraiment le surcoût et l’encombrement ?
Merci pour votre retour, et c’est très pertinent de souligner que l’économie réalisée sur le 8 pouces peut être réinvestie dans de meilleurs oculaires. Pour les nébuleuses faibles, le gain du 10 pouces est réel, mais il est souvent plus subtil qu’on ne l’imagine, et le compromis sur le poids et l’encombrement est très concret. Je vous conseillerais de consulter des forums comme “Stargazers Lounge” où de nombreux utilisateurs comparent directement leurs observations avec ces deux diamètres. N’hésitez pas à nous dire vers quel modèle vous vous orientez finalement !
A 10-inch dob is typically faster than f/5 and may require more selective eyepieces, but both sizes offer excellent viewing experiences.
I’ve owned various models and now prefer a 4.5″ f/8, 8″ f/6, and 12″ f/5 for my collection. While I’ve observed through 16″ scopes, I’m content with my current setup for now.
I upgraded from a 114 Tasco to a 10″ dob. I initially considered an 8″ but caught aperture fever, so I went bigger. It arrives Friday, and I’ll be watching for the delivery truck until then.
I’m also leaning toward the 10-inch. Which brand did you choose?
I chose the Starfield, the only GSO-made option available in Canada. It had better accessories than both Skywatcher and Explore Scientific, and the Celestron was significantly more expensive.
I’ll consider that telescope.
I’ll be sure to post a mini-review once I receive it.
An 8-inch Dobsonian can serve you well for years. A 10-inch model will provide better light gathering and resolution, but it’s less portable. Keep in mind that Dobsonians aren’t ideal for astrophotography—you’ll need an equatorial mount for that.
I bought the 10″ and have no regrets—it’s an amazing scope. I even made a post about struggling to decide between the 8″ and 10″ myself. You might find it helpful to check it out.
Thank you for the information.
As an owner of both 8″ and 10″ dobsonians, I’d recommend the 10″ unless portability is a major concern. The weight difference isn’t dramatic, but the 10″ is noticeably bulkier and more awkward to move through doorways and in and out of a car. I can easily carry my 8″ tube with one arm, while I use lifting straps for the 10″ for convenience.
Regarding go-to functionality, it’s nice to have if it fits your budget. However, I’d suggest a manual dob and putting the savings toward quality eyepieces instead.
Since you mentioned planetary observation, you might also consider a Maksutov-Cassegrain or Schmidt-Cassegrain telescope for their good focal length value. Keep in mind you’ll need to budget for a mount as well. The Celestron NexStar series offers solid complete packages, though I’d avoid the 8SE as it’s undermounted based on my experience.
This hobby can quickly become expensive, which is why many recommend starting with a Newtonian on a manual dob base.
I found a 10-inch Dobsonian on Facebook Marketplace that I plan to check out soon. Since I drive a truck, transportation shouldn’t be a problem.
A good general rule is to choose the largest aperture you can afford, while also considering factors like portability and ease of setup. Keep in mind that larger apertures often come with a higher price for comparable quality. You’ll need to decide whether to prioritize size over quality or save up for a larger scope that still meets your standards. Ultimately, it’s about finding the right balance—maximizing aperture without significantly compromising on build quality.
How can I determine if I’m getting a higher quality telescope? Is price the only indicator?
Don’t worry too much about the scope’s quality. While there are upgrades available, I’d suggest saving that money for a couple of quality eyepieces instead.
Use this astronomy tools calculator to compare views through an 8-inch and 10-inch Dobsonian by targeting Saturn or the Moon with their included eyepieces. I recommend eventually getting two additional eyepieces and a Barlow lens – one for wide-field views and another for planetary observation, paired with a 2x or 3x Barlow. Personally, I use a 10-inch Dob with a 24mm Panoptic, 9mm Nagler, and 2x Barlow for about 90% of my viewing.
Your eyepiece collection should eventually cover several useful magnifications for your preferred targets. Before buying any new eyepiece, check it in the calculator against your current gear. If it doesn’t offer a noticeably different field of view from what you already have, skip it – unless you’re replacing lower-quality glass.
Quality eyepieces and filters aren’t cheap, and you’ll likely invest more in accessories than the telescope itself if you stay with the hobby long-term.
Regarding telescope upgrades: you could improve the spider vanes, add a dew shield, upgrade the focuser, or enhance the base pivot points. Push-to or go-to features are available too, but for visual astronomy, these matter less. For deep-sky astrophotography, guiding becomes crucial – I maintain a separate setup for that purpose since Dobsonians work best for visual observation and basic planetary imaging.
To gauge the quality of a telescope, research the brand, model, and reviews. CloudyNights.com is a well-respected forum for amateur astronomy where you can find extensive information.
I recommend selecting two scopes you’re interested in based on price and aperture, then checking their reviews on CloudyNights. Even reputable brands sometimes have models with flaws that could affect your enjoyment, but a bit of research can help you avoid these and find a better option within your budget.
Ed Ting on YouTube recommends the 8-inch as the sweet spot between aperture and portability. He notes that the 10-inch doesn’t offer enough of a visual improvement to justify its larger size, which affects both portability and ease of movement in the alt-azimuth mount.
Thank you for the information.
If the slightly larger size isn’t a problem for you, then definitely go with the 10-inch.
I don’t think it will be an issue.
I’m considering the new Explore Scientific 10-inch dob. At 45 pounds, it’s comparable in weight to standard 8-inch models, giving you the best of both worlds.
The only drawback is that this is a new lineup, so there aren’t any reviews or user feedback available yet.
I had the same dilemma. A survey of astronomy clubs showed that 8″ dobs are the most popular among members because they’re easier to transport and the mirror cools down faster. I decided I’d rather have a scope I’ll use regularly, even with slightly less brightness, so I went with the 8″. It seems to be a good sweet spot.
The 10-inch will perform slightly better, especially for deep space objects, but the difference isn’t dramatic.
Having owned both sizes, I found the 10-inch can be bulky and unwieldy. There were nights I didn’t even want to deal with it. So while the 10-inch offers marginally better views, it’s also more of a hassle to move around.
For the same budget, I’d choose an 8-inch with a quality eyepiece over a 10-inch.
The 10″ dob will offer a slight advantage, but keep in mind that it typically has a faster focal ratio, moving from around f/6 with an 8″ to f/5 or so. This makes collimation more critical and may require adjustment after significant moves.
Manual dobsonians are not ideal for imaging. For bright targets like planets or parts of the Moon, you would need to use the drifting method with a planetary camera. Additionally, most Dobsonian tubes cannot achieve focus with a DSLR, though there are exceptions like the SkyWatcher 200P and 250P classic models.
These models are easier to transport due to built-in handles, but accessories and mount smoothness can vary by brand and may be better elsewhere.