eso.org

We performed a comprehensive analysis of eso.org on 2026-06-29. The website returned an HTTP 200 status code with a server response time of 14794ms. The page is served over HTTP/1.1 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 183 KB. The website uses a secure HTTPS connection with a valid SSL certificate issued by Hellenic Academic and Research Institutions CA (DV type). The connection is encrypted using TLS 1.2 with the ECDHE-RSA-AES128-GCM-SHA256 cipher suite and sha256WithRSAEncryption signature algorithm. The certificate covers 53 domain(s) (Subject Alternative Names) and expires on 2026-10-08, which is 101 days from now. The security headers analysis reveals a score of 20/100 (poor). The following security headers are properly configured: Strict-Transport-Security (HSTS). However, the site is missing Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy, which could expose the site and its users to cross-site scripting (XSS), clickjacking, and other web-based attacks. Our technology detection scan identified 4 technologies across 4 categories powering eso.org. The detected stack includes Matomo, reCAPTCHA v3, StackPath, and YouTube Embed. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, eso.org receives an overall trust score of 70/100, classified as "Likely Safe".

After conducting a thorough safety and legitimacy analysis, eso.org receives a trust score of 70/100, which places it in the "Likely Safe" category. This score is calculated by evaluating multiple factors including SSL certificate validity, domain registration history, email authentication protocols, security header configuration, and blacklist status across major threat intelligence databases. The analysis identified several positive trust signals: a valid HTTPS connection protecting data in transit, HSTS (HTTP Strict Transport Security) enforcement preventing protocol downgrade attacks, a valid SSL certificate issued by Hellenic Academic and Research Institutions CA with 101 days until expiration, SPF (Sender Policy Framework) email authentication preventing email spoofing, and DMARC email authentication with a none policy. Areas of concern include: the absence of a Content-Security-Policy header, which leaves the site more vulnerable to cross-site scripting (XSS) attacks, no X-Frame-Options header, which could allow the site to be embedded in malicious iframes (clickjacking), missing Referrer-Policy, potentially leaking URL information to third parties, the domain's WHOIS information is hidden behind a privacy service, making it harder to verify the owner's identity, and DNSSEC is not enabled, leaving DNS queries vulnerable to spoofing attacks. While these issues don't necessarily indicate malicious intent, they represent areas where the website's security posture could be improved. We checked eso.org against 8 major blacklist databases including Google Safe Browsing, Phishtank, Urlhaus, Openphish, Dnsfilter, Spamhaus Dbl, Surbl, and Virustotal. The domain passed all 8 checks with a clean status, meaning it has not been flagged for phishing, malware distribution, spam, or other malicious activities by any of the tested threat intelligence providers.

Our technology detection engine scanned eso.org and identified 4 distinct technologies across 4 categories. This analysis is performed by examining HTTP response headers, HTML source code patterns, JavaScript library fingerprints, CSS framework signatures, and DNS records. Analytics: Matomo — tracks visitor behavior and provides traffic insights for eso.org. Security: reCAPTCHA v3 — provides security features like bot detection and CAPTCHA for eso.org. CDN: StackPath — accelerates content delivery by caching assets at edge locations worldwide for eso.org. Video: YouTube Embed — provides video hosting and playback for eso.org.

eso.org delivers its homepage in 14794ms (server response time), which is considered slow by industry standards. The total page weight is 183 KB, and we detected 392 resource requests loading assets from 18 third-party domains. A high number of third-party domains can significantly impact page load time due to additional DNS lookups and TLS handshakes required for each domain. The website uses Gzip compression for text-based assets, achieving an estimated 60.0% reduction in transfer size. This reduces bandwidth usage and improves page load times, especially for visitors on slower connections. Asset minification status: 0 out of 2 CSS files and 0 out of 2 JavaScript files are minified. Minifying the remaining 4 unminified file(s) could further reduce page weight by 10-30% for those assets. Minification is a best practice that reduces download sizes without affecting functionality. From an environmental perspective, each page view of eso.org produces approximately 0.09g of CO₂, earning a carbon rating of A. This places the website among the cleanest on the web, demonstrating efficient use of server resources and optimized content delivery. For reference, the average web page produces about 0.5g of CO₂ per page view. The page weight of 183 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for eso.org. This typically means the site doesn't have enough real-world Chrome user traffic to generate statistically significant field data, or the domain is not included in the CrUX dataset. Core Web Vitals (LCP, INP, CLS) are important Google ranking factors that measure real user experience.

eso.org resolves to the IPv4 address 134.171.75.1, but does not support IPv6. IPv6 adoption is increasingly important as IPv4 address space becomes exhausted, and some ISPs and regions are transitioning to IPv6-only connectivity. The domain has 1 A record(s) configured. The domain name system is managed by 4 name servers: dnsslave1.hq.eso.org, dnsslave1.sc.eso.org, dnsslave2.hq.eso.org, and dnsslave2.sc.eso.org. Having 4 name servers provides good redundancy — if one fails, the others can continue serving DNS queries. The choice of name servers often indicates the DNS hosting provider or CDN service being used. Email for eso.org is handled by Microsoft 365 with 1 MX records configured: eso-org.mail.protection.outlook.com. Multiple MX records provide failover redundancy — if the primary mail server is unavailable, email will be routed to the next available server. SPF (Sender Policy Framework) is configured, which specifies which mail servers are authorized to send email on behalf of this domain. This helps prevent email spoofing and improves email deliverability. DMARC (Domain-based Message Authentication, Reporting and Conformance) is configured with a none policy — a monitoring-only setting that doesn't enforce any action on unauthorized emails. DKIM was not detected. Without DKIM, recipients cannot cryptographically verify that emails claiming to be from this domain are authentic. DNSSEC is not enabled for eso.org. While not critical for most websites, DNSSEC adds an important security layer by ensuring DNS responses haven't been tampered with during transit. Enabling DNSSEC is recommended for domains handling sensitive data or financial transactions.

The homepage of eso.org contains 2,829 words of visible text content. This is a substantial amount of content that provides good opportunities for search engine indexing. The page is structured with 5 H2 headings, 0 H3 headings, 0 H4 headings. The page includes 22 images. 2 images (9%) are missing alt text attributes, which is a significant concern for both accessibility and SEO. Screen readers rely on alt text to describe images to visually impaired users, and search engines use alt text to understand image content. Only 91% of images have proper alt text — we recommend adding descriptive alt attributes to all images. The link structure consists of 320 internal links pointing to other pages on the same domain and 24 external links pointing to third-party websites. The high number of internal links suggests a well-interconnected site structure, which helps search engines discover and crawl all pages efficiently. There are 2 external JavaScript files, 2 CSS stylesheets, and 0 iframes on the page. The site implements the following web standards and features: robots.txt (controls search engine crawling behavior) and RSS feed for content syndication. Notable missing features: XML Sitemap and Schema.org structured data. Adding these could improve search engine discoverability and rich result eligibility. We detected the following payment methods accepted on eso.org: Discover. Offering multiple payment options including credit cards and digital wallets improves customer trust and can increase conversion rates. The website has social media presence across 4 platforms: Facebook (@ESOAstronomy), Instagram (@esoastronomy), Linkedin (@european-southern-observatory), and Youtube (@UCIhYoC2VIAJqCkoIWNHBQ3Q). An active social media presence is a positive trust indicator and helps build brand awareness and customer engagement.

The title tag for eso.org is good at 3 characters: "ESO". The length is acceptable, though it may be slightly truncated in some search result displays. The meta description is 79 characters (well-optimized): "ESO, European Organisation for Astronomical Research in the Southern Hemisphere". Google typically displays up to 155-160 characters of the meta description in search results. A compelling meta description with a clear call-to-action can significantly improve click-through rates from search results. The page language is declared as en, the meta robots directive is set to index,follow, and a favicon is configured. Open Graph meta tags are configured with 3/4 recommended fields: OG title ("ESO — The European Southern Observatory..."), OG description, OG image (social sharing thumbnail), These tags control how the page appears when shared on Facebook, LinkedIn, and other social media platforms that support the Open Graph protocol. A Twitter Card of type summary is configured, which controls how links appear when shared on Twitter/X. The "summary" type displays a large image preview, which typically generates higher engagement rates than the basic card type. The meta keywords tag contains 23 terms including ESO, eso.org, Astronomy, Astrophysics, and Astronomie. Note: Google has officially confirmed that it does not use the meta keywords tag as a ranking signal. However, some other search engines (Bing, Yandex) may still reference it.